Laboratoire Kastler Brossel (Paris / 1998....).
Overview
Works:  32 works in 32 publications in 2 languages and 32 library holdings 

Roles:  Other 
Publication Timeline
.
Most widely held works by
Laboratoire Kastler Brossel (Paris / 1998....).
Experimental study of metastable solid and superfluid helium4 by
An Qu(
)
1 edition published in 2017 in English and held by 1 WorldCat member library worldwide
Metastable solid helium is a possible candidate for supersolidity. In 2011, our group has demonstrated that we could obtain the metastable solid helium at pressures below the melting pressure using a focused acoustic wave. However, an unexpected instability occurs when the local pressure of the crystal reaches 21 bar which is 4 bar below the melting pressure. So I started my thesis by studying the appearance time of the instability, and I confirmed that it always appears at the low pressure swing of the acoustic wave. Then, I studied the cavitation limit of superfluid helium at negative pressure. Using an interferometric method developed by my predecessor Fabien Souris, I directly measured the cavitation density of metastable superfluid helium. I found that at 1 K, superfluid helium cavitates when its local density is lowered by 8.4%. Using a theoretically wellestablished equation of state, this result can be converted to a cavitation pressure in order to compare our results with those obtained by others groups. To my surprise, my result is not consistent with the others'. This incompatibility raises interesting questions about the possibility of nucleation of the bubble on quantified vortices. Finally, I studied the dynamics of the helium bubble triggered by cavitation. By analyzing the equation of motion of bubble and the corresponding heat transfer, I have successfully explained why the bubble's lifetime has a dramatic transition as the helium passes from normal liquid to superfluid
1 edition published in 2017 in English and held by 1 WorldCat member library worldwide
Metastable solid helium is a possible candidate for supersolidity. In 2011, our group has demonstrated that we could obtain the metastable solid helium at pressures below the melting pressure using a focused acoustic wave. However, an unexpected instability occurs when the local pressure of the crystal reaches 21 bar which is 4 bar below the melting pressure. So I started my thesis by studying the appearance time of the instability, and I confirmed that it always appears at the low pressure swing of the acoustic wave. Then, I studied the cavitation limit of superfluid helium at negative pressure. Using an interferometric method developed by my predecessor Fabien Souris, I directly measured the cavitation density of metastable superfluid helium. I found that at 1 K, superfluid helium cavitates when its local density is lowered by 8.4%. Using a theoretically wellestablished equation of state, this result can be converted to a cavitation pressure in order to compare our results with those obtained by others groups. To my surprise, my result is not consistent with the others'. This incompatibility raises interesting questions about the possibility of nucleation of the bubble on quantified vortices. Finally, I studied the dynamics of the helium bubble triggered by cavitation. By analyzing the equation of motion of bubble and the corresponding heat transfer, I have successfully explained why the bubble's lifetime has a dramatic transition as the helium passes from normal liquid to superfluid
Quantumenhanced sensing and synthetic Landau levels with ultracold dysprosium atoms by
Thomas Chalopin(
)
1 edition published in 2019 in English and held by 1 WorldCat member library worldwide
Cette thèse porte sur des études expérimentales basées sur les interactions entre photons et atomes ultrafroids de dysprosium. La structure électronique du dysprosium est à l'origine de ses propriétés atomiques singulières, donnant accès à une phénoménologie physique diversifiée. Dans la première partie, nous donnons une description globale de notre expérience, et du protocole expérimental qui permet la production de gaz dégénérés de dysprosium bosonique. Une étape importante de notre séquence expérimentale porte sur l'utilisation de la raie d'intercombinaison à 626 nm pour le refroidissement Doppler d'atomes piégés. Nous montrons que la forte anisotropie de la polarisabilité de l'état excité est bénéfique pour le refroidissement évaporatif qui suit. Dans la deuxième partie, nous présentons des expériences qui utilisent le couplage entre les photons et le spin, inhérent à cette transition, pour manipuler les états internes des atomes et réaliser des états nonclassiques de spin. Nous nous concentrons sur la réalisation d'états N00N, correspondant à la superposition d'états classiques ayant des aimantations opposées. Nous démontrons expérimentalement que la sensibilité aux champs magnétiques de ces états est proche de la limite de Heisenberg. La dernière partie est dédiée à l'effet Hall quantique, que nous étudions en encodant une dimension synthétique dans les états internes des atomes. Nous réalisons un système analogue aux niveaux de Landau à l'aide d'un couplage spinorbite. Nous observons les propriétés du niveau de Landau fondamental : une dispersion supprimée, des états de bords chiraux, ainsi qu'une réponse de Hall caractéristique d'une topologie nontriviale
1 edition published in 2019 in English and held by 1 WorldCat member library worldwide
Cette thèse porte sur des études expérimentales basées sur les interactions entre photons et atomes ultrafroids de dysprosium. La structure électronique du dysprosium est à l'origine de ses propriétés atomiques singulières, donnant accès à une phénoménologie physique diversifiée. Dans la première partie, nous donnons une description globale de notre expérience, et du protocole expérimental qui permet la production de gaz dégénérés de dysprosium bosonique. Une étape importante de notre séquence expérimentale porte sur l'utilisation de la raie d'intercombinaison à 626 nm pour le refroidissement Doppler d'atomes piégés. Nous montrons que la forte anisotropie de la polarisabilité de l'état excité est bénéfique pour le refroidissement évaporatif qui suit. Dans la deuxième partie, nous présentons des expériences qui utilisent le couplage entre les photons et le spin, inhérent à cette transition, pour manipuler les états internes des atomes et réaliser des états nonclassiques de spin. Nous nous concentrons sur la réalisation d'états N00N, correspondant à la superposition d'états classiques ayant des aimantations opposées. Nous démontrons expérimentalement que la sensibilité aux champs magnétiques de ces états est proche de la limite de Heisenberg. La dernière partie est dédiée à l'effet Hall quantique, que nous étudions en encodant une dimension synthétique dans les états internes des atomes. Nous réalisons un système analogue aux niveaux de Landau à l'aide d'un couplage spinorbite. Nous observons les propriétés du niveau de Landau fondamental : une dispersion supprimée, des états de bords chiraux, ainsi qu'une réponse de Hall caractéristique d'une topologie nontriviale
Étude de la structure fine de l'état excité des centres F dans les halogénures alcalins by
Robert Romestain(
)
1 edition published in 1965 in French and held by 1 WorldCat member library worldwide
1 edition published in 1965 in French and held by 1 WorldCat member library worldwide
Coherence and relaxation of an opticallydriven bosonic quantum gas : experiments with ultracold ytterbium atoms by
Manel Bosch Aguilera(
)
1 edition published in 2019 in English and held by 1 WorldCat member library worldwide
In this thesis I report on a series of experimental studies performed with ultracold ytterbium gases driven in different optical transitions. Ytterbium belongs to the family of the socalled alkalineearthlike atoms, which feature a rich electronic structure, with an optical clock transition free of spontaneous emission, and a narrow intercombination transition, making them very appealing for metrological and quantum simulation proposals. By performing spectroscopy on the clock transition, I prove on a first set of experiments in deep optical lattices our ability to drive this transition coherently for long times. This coherent control is then used for different studies. First, as tool to measure the scattering lengths of the states involved in the clock transition. Then, to prepare a small open quantum system, where dissipation arises in the form of twobody losses. By enabling the coupling adiabatically, we observe a strong suppression of these losses, which is interpreted as a signature of the quantum Zeno effect. I ultimately use the coherent driving to study the relaxation dynamics of a dissipative bulk BoseEinstein condensate. Finally, I elaborate an investigation on a stronglyinteracting open system. Dissipation is artificially induced in the form of spontaneous emission using the intercombination transition. Here, I study in which manner spontaneous emission destroys the spatial coherence of a superfluid in an optical lattice. These experiments reveal that the presence of strong interactions partially protects a residual amount of coherence and makes decoherence develop in a nontrivial manner, unveiling the emergence of a subdiffusive relaxation channel
1 edition published in 2019 in English and held by 1 WorldCat member library worldwide
In this thesis I report on a series of experimental studies performed with ultracold ytterbium gases driven in different optical transitions. Ytterbium belongs to the family of the socalled alkalineearthlike atoms, which feature a rich electronic structure, with an optical clock transition free of spontaneous emission, and a narrow intercombination transition, making them very appealing for metrological and quantum simulation proposals. By performing spectroscopy on the clock transition, I prove on a first set of experiments in deep optical lattices our ability to drive this transition coherently for long times. This coherent control is then used for different studies. First, as tool to measure the scattering lengths of the states involved in the clock transition. Then, to prepare a small open quantum system, where dissipation arises in the form of twobody losses. By enabling the coupling adiabatically, we observe a strong suppression of these losses, which is interpreted as a signature of the quantum Zeno effect. I ultimately use the coherent driving to study the relaxation dynamics of a dissipative bulk BoseEinstein condensate. Finally, I elaborate an investigation on a stronglyinteracting open system. Dissipation is artificially induced in the form of spontaneous emission using the intercombination transition. Here, I study in which manner spontaneous emission destroys the spatial coherence of a superfluid in an optical lattice. These experiments reveal that the presence of strong interactions partially protects a residual amount of coherence and makes decoherence develop in a nontrivial manner, unveiling the emergence of a subdiffusive relaxation channel
Spatial mode multiplexing : from fundamental concepts to applications by
Pauline Boucher(
)
1 edition published in 2018 in English and held by 1 WorldCat member library worldwide
This thesis is dedicated to spatial mode multiplexing, from its fundamental concepts to its applications. The work is associated with the multiplane light converter (MPLC) technology developed by CAILabs. This study is divided into two main parts. First, we investigate the use of independent spatial mode shaping to measure or modify spatial parameters of the electromagnetic field. We make the theoretical demonstration that the best sensitivity for the measurement of small displacements of a beam  or of the distance between two incoherent beams  is reached when an intensity measurement is made on the HermiteGaussian mode basis. By building the adequate MPLC system, we make the experimental validation of this result. We also make the demonstration that a MPLC system can be designed and used to transfer the control of one spatial parameter of a beam onto another. We built an experimental setup which allows to control the position of the focal point of a beam using transverse displacement and tilt. The second project we conducted was a theoretical and numerical study of the statistical transport properties of the MPLC using tools from random matrix theory. We aim at identifying the underlying physical processes which make up for the efficiency of this transformation technique
1 edition published in 2018 in English and held by 1 WorldCat member library worldwide
This thesis is dedicated to spatial mode multiplexing, from its fundamental concepts to its applications. The work is associated with the multiplane light converter (MPLC) technology developed by CAILabs. This study is divided into two main parts. First, we investigate the use of independent spatial mode shaping to measure or modify spatial parameters of the electromagnetic field. We make the theoretical demonstration that the best sensitivity for the measurement of small displacements of a beam  or of the distance between two incoherent beams  is reached when an intensity measurement is made on the HermiteGaussian mode basis. By building the adequate MPLC system, we make the experimental validation of this result. We also make the demonstration that a MPLC system can be designed and used to transfer the control of one spatial parameter of a beam onto another. We built an experimental setup which allows to control the position of the focal point of a beam using transverse displacement and tilt. The second project we conducted was a theoretical and numerical study of the statistical transport properties of the MPLC using tools from random matrix theory. We aim at identifying the underlying physical processes which make up for the efficiency of this transformation technique
Preparation of large cold atomic ensembles and applications in efficient lightmatter interfacing by
Pierre VernazGris(
)
1 edition published in 2018 in English and held by 1 WorldCat member library worldwide
This cotutelle PhD thesis revolves around quantum optics experiments which involve large atomic ensembles. The study of lightmatter interaction and its enhancement are crucial steps in the development and progress of quantum information generation, storage and processing protocols. The work presented here focuses on the evolution of large atomic ensemble preparation techniques, on the development and experimental investigation of stopped and stationary light protocols. Lasercooled atomic ensembles in both experimental realisations have been brought to optical depths of a few hundreds, at temperatures of tens of microkelvin. Moreover, addressing these ensembles in symmetric configurations has enabled the study of protocols based on the temporal reversal of the mapping of light to collective atomic excitations. These enhancements have led to the storage of qubits based on electromagneticallyinduced transparency, and the optical storage in a backwardretrieval Raman scheme, both demonstrating efficiency records, above 50%. This work has also led to the experimental investigation of stationary light and new protocols based on it
1 edition published in 2018 in English and held by 1 WorldCat member library worldwide
This cotutelle PhD thesis revolves around quantum optics experiments which involve large atomic ensembles. The study of lightmatter interaction and its enhancement are crucial steps in the development and progress of quantum information generation, storage and processing protocols. The work presented here focuses on the evolution of large atomic ensemble preparation techniques, on the development and experimental investigation of stopped and stationary light protocols. Lasercooled atomic ensembles in both experimental realisations have been brought to optical depths of a few hundreds, at temperatures of tens of microkelvin. Moreover, addressing these ensembles in symmetric configurations has enabled the study of protocols based on the temporal reversal of the mapping of light to collective atomic excitations. These enhancements have led to the storage of qubits based on electromagneticallyinduced transparency, and the optical storage in a backwardretrieval Raman scheme, both demonstrating efficiency records, above 50%. This work has also led to the experimental investigation of stationary light and new protocols based on it
Quantum sensing with Rydberg Schrödinger cat states by
EvaKatharina Dietsche(
)
1 edition published in 2017 in English and held by 1 WorldCat member library worldwide
Rydberg atoms are highly excited states, in which the electron is orbiting far from the nucleus. Their large electric dipole makes them very sensitive to their electromagnetic environment. Using a combination of microwave and radiofrequency fields, we engineer nonclassical quantum states specifically designed to exploit at best this sensitivity for electric and magnetic field metrology. In the first part, we prepare nonclassical states, similar to Schrödinger cat states, superpositions of two orbitals with very different polarizabilities, that allow us to measure small variations of the static electric field with a sensitivity well beyond the standard quantum limit and close to the fundamental Heisenberg limit. We reach a single atom sensitivity of 30mV/m for a 200ns interrogation time. It makes our system one of the most sensitive electrometers to date. We then implement more complex manipulations of the atom. Using a spinecho technique taking advantage of the full extent of the Rydberg manifold, we perform a correlation function measurement of the electric field with a MHz bandwidth.In the final part, we prepare a quantum superposition of two circular states with opposite magnetic quantum numbers. It corresponds to an electron rotating at the same time in opposite directions on the same orbit, a rather nonclassical situation. The huge difference of magnetic moment between the two components of the superposition, in the order of 100muB, opens the way to the measurement of small variations of the magnetic field with a high bandwidth
1 edition published in 2017 in English and held by 1 WorldCat member library worldwide
Rydberg atoms are highly excited states, in which the electron is orbiting far from the nucleus. Their large electric dipole makes them very sensitive to their electromagnetic environment. Using a combination of microwave and radiofrequency fields, we engineer nonclassical quantum states specifically designed to exploit at best this sensitivity for electric and magnetic field metrology. In the first part, we prepare nonclassical states, similar to Schrödinger cat states, superpositions of two orbitals with very different polarizabilities, that allow us to measure small variations of the static electric field with a sensitivity well beyond the standard quantum limit and close to the fundamental Heisenberg limit. We reach a single atom sensitivity of 30mV/m for a 200ns interrogation time. It makes our system one of the most sensitive electrometers to date. We then implement more complex manipulations of the atom. Using a spinecho technique taking advantage of the full extent of the Rydberg manifold, we perform a correlation function measurement of the electric field with a MHz bandwidth.In the final part, we prepare a quantum superposition of two circular states with opposite magnetic quantum numbers. It corresponds to an electron rotating at the same time in opposite directions on the same orbit, a rather nonclassical situation. The huge difference of magnetic moment between the two components of the superposition, in the order of 100muB, opens the way to the measurement of small variations of the magnetic field with a high bandwidth
Control of light in a disordered medium with gain : wavefrontshaping the pump in fiber amplifiers and fiber lasers by
Tom Sperber(
)
1 edition published in 2019 in English and held by 1 WorldCat member library worldwide
The recent advent of wavefrontshaping techniques has demonstrated the ability to control the propagation of light through a broad range of complex media, amongst them multimode fibers. The case of a multimode fiber which is also a gain medium presents increased complexity, since the pump beam, in itself multimode, may act upon the signal light in specklelike spatial profiles of amplification. The resulting heterogeneous gain may be viewed as analogous to a nonunitary scattering process. Interest in the study of such systems has recently risen in several domains, such as optical communications, highpower fiber lasers, and random lasers. In this work, we consider a multimode fiber doped by a rareearth element, and pumped by a coherent pump beam that passes through a wavefront shaping scheme, rendering the modal composition of the excitation within the fiber configurable. We explore the possibility of harnessing the degrees of freedom thus offered in the pumping, for controlling the output signal of such a gain system. A theoretical model and its implementation as a numerical solver serve to quantify the degree of achievable control, as well as providing insights into the fundamental mechanisms limiting it. In an amplifier configuration, the experimental work successfully validated the model's predictions by showing a significant effect of the wavefront shaping of the pump upon the speckle at the amplifier's output. In the lasing cavity configuration, the experimental work demonstrated the ability of the pump modulation scheme to influence the lasing emission, in particular to favor or suppress chosen lasing modes
1 edition published in 2019 in English and held by 1 WorldCat member library worldwide
The recent advent of wavefrontshaping techniques has demonstrated the ability to control the propagation of light through a broad range of complex media, amongst them multimode fibers. The case of a multimode fiber which is also a gain medium presents increased complexity, since the pump beam, in itself multimode, may act upon the signal light in specklelike spatial profiles of amplification. The resulting heterogeneous gain may be viewed as analogous to a nonunitary scattering process. Interest in the study of such systems has recently risen in several domains, such as optical communications, highpower fiber lasers, and random lasers. In this work, we consider a multimode fiber doped by a rareearth element, and pumped by a coherent pump beam that passes through a wavefront shaping scheme, rendering the modal composition of the excitation within the fiber configurable. We explore the possibility of harnessing the degrees of freedom thus offered in the pumping, for controlling the output signal of such a gain system. A theoretical model and its implementation as a numerical solver serve to quantify the degree of achievable control, as well as providing insights into the fundamental mechanisms limiting it. In an amplifier configuration, the experimental work successfully validated the model's predictions by showing a significant effect of the wavefront shaping of the pump upon the speckle at the amplifier's output. In the lasing cavity configuration, the experimental work demonstrated the ability of the pump modulation scheme to influence the lasing emission, in particular to favor or suppress chosen lasing modes
Localisation d'Anderson avec des atomes froids : dynamique dans le désordre et perspectives avec des modèles chaotiques by
Tony Prat(
)
1 edition published in 2017 in English and held by 1 WorldCat member library worldwide
This thesis theoretically investigates several effects related to Anderson localization, focusing on the context of disordered and chaotic coldatomic systems. In coldatomic systems, optical speckle patterns are often used to create the disorder. The resulting potentials felt by the atoms differ from Gaussian random potentials, commonly assumed in the description of condensedmatter systems. In the first part of the thesis, we discuss their specificities, with an emphasis on the spectral properties. Atomoptics experiments offer interesting possibilities, such as the possibility to directly probe the atoms inside the disordered potential. In view of these possibilities, we consider in the second part of the thesis the spreading of matter wave packets initially launched with a nonzero velocity. We find that after an initial ballistic motion, the packet centerofmass experiences a retroreflection and slowly returns to its initial position, mimicking a boomerang. Atomatom interactions are then introduced in a third part. We consider dilute condensed bosonic gases, and treat the interactions at the meanfield (GrossPitaevskii) level. Various situations are studied numerically, in particular the quantum boomerang scenario, and the dynamical spreading both in momentum and energy of matter waves prepared as plane waves. In the last part, we show that chaotic models offer interesting prospects for the study of Anderson localization. On the one hand, we present strong evidences in favor of a spinless kicked rotor in the sympletic ensemble. On the other hand, a second look at a commonly studied quasiperiodically modulated kicked rotor reveals intriguing results
1 edition published in 2017 in English and held by 1 WorldCat member library worldwide
This thesis theoretically investigates several effects related to Anderson localization, focusing on the context of disordered and chaotic coldatomic systems. In coldatomic systems, optical speckle patterns are often used to create the disorder. The resulting potentials felt by the atoms differ from Gaussian random potentials, commonly assumed in the description of condensedmatter systems. In the first part of the thesis, we discuss their specificities, with an emphasis on the spectral properties. Atomoptics experiments offer interesting possibilities, such as the possibility to directly probe the atoms inside the disordered potential. In view of these possibilities, we consider in the second part of the thesis the spreading of matter wave packets initially launched with a nonzero velocity. We find that after an initial ballistic motion, the packet centerofmass experiences a retroreflection and slowly returns to its initial position, mimicking a boomerang. Atomatom interactions are then introduced in a third part. We consider dilute condensed bosonic gases, and treat the interactions at the meanfield (GrossPitaevskii) level. Various situations are studied numerically, in particular the quantum boomerang scenario, and the dynamical spreading both in momentum and energy of matter waves prepared as plane waves. In the last part, we show that chaotic models offer interesting prospects for the study of Anderson localization. On the one hand, we present strong evidences in favor of a spinless kicked rotor in the sympletic ensemble. On the other hand, a second look at a commonly studied quasiperiodically modulated kicked rotor reveals intriguing results
High precision tests of QED : measurement of the alphaparticle and helion rms charge radius and the transition energies in
highlycharged ions by
Jorge Felizardo Dias Cunha Machado(
)
1 edition published in 2018 in English and held by 1 WorldCat member library worldwide
1 edition published in 2018 in English and held by 1 WorldCat member library worldwide
Effets électrodynamiques et nucléaires quantiques dans les ions de type lithium et les atomes muoniques by
Guojie Bian(
)
1 edition published in 2019 in English and held by 1 WorldCat member library worldwide
Nous avons effectué des calculs DiracFock multiconfiguration des énergies de transitions de structure fine 1s²2p²PJ1s²2s²S1/2, J=1/2, 3/2, les transitions à partir d'états excités en couche internes 1s2s2p²PJ1s²2s²S1/2, J=1/2, 3/2 et 1s2s2p4PJ1s²2s²S1/2, J=1/2, 3/2, 5/2, et les transitions Auger à partir de ces mêmes états 1s2s2p4PJ 1s2 1S0, J=1/2, 3/2 dans la séquence isoélectronique du lithium, pour des ions de numéro atomique 10 ≤ Z ≤ 96. Des corrections électrodynamiques quantiques avec modèle d'opérateur efficace et des corrections de corrélation électronique sont incluses dans les fonctions d'onde de Dirac avec une taille nucléaire finie. Des corrections de polarisation de Breit et de polarisation du vide de tous les ordres sont également incluses dans le calcul, avec une fonction d'onde d'ensemble actif entièrement optimisée. Des comparaisons approfondies entre les résultats théoriques existants et l'expérience sont effectuées. Nous évaluons également les paramètres nucléaires qui minimisent l'écart pondéré entre la théorie et l'expérience dans les modèles muoniques 208Pb avec des modèles Fermi à deux paramètres et Gauss à trois paramètres. Nous avons obtenu r = 5.5057 fm dans le modèle de Fermi et r = 5.5031 dans le modèle de Gauss par ajustement polynomial. Nous analysons également les contributions individuelles de 226Ra et 248Cm muoniques en utilisant la même prescription de corrections exactes de QED pour les expériences à venir
1 edition published in 2019 in English and held by 1 WorldCat member library worldwide
Nous avons effectué des calculs DiracFock multiconfiguration des énergies de transitions de structure fine 1s²2p²PJ1s²2s²S1/2, J=1/2, 3/2, les transitions à partir d'états excités en couche internes 1s2s2p²PJ1s²2s²S1/2, J=1/2, 3/2 et 1s2s2p4PJ1s²2s²S1/2, J=1/2, 3/2, 5/2, et les transitions Auger à partir de ces mêmes états 1s2s2p4PJ 1s2 1S0, J=1/2, 3/2 dans la séquence isoélectronique du lithium, pour des ions de numéro atomique 10 ≤ Z ≤ 96. Des corrections électrodynamiques quantiques avec modèle d'opérateur efficace et des corrections de corrélation électronique sont incluses dans les fonctions d'onde de Dirac avec une taille nucléaire finie. Des corrections de polarisation de Breit et de polarisation du vide de tous les ordres sont également incluses dans le calcul, avec une fonction d'onde d'ensemble actif entièrement optimisée. Des comparaisons approfondies entre les résultats théoriques existants et l'expérience sont effectuées. Nous évaluons également les paramètres nucléaires qui minimisent l'écart pondéré entre la théorie et l'expérience dans les modèles muoniques 208Pb avec des modèles Fermi à deux paramètres et Gauss à trois paramètres. Nous avons obtenu r = 5.5057 fm dans le modèle de Fermi et r = 5.5031 dans le modèle de Gauss par ajustement polynomial. Nous analysons également les contributions individuelles de 226Ra et 248Cm muoniques en utilisant la même prescription de corrections exactes de QED pour les expériences à venir
Ingénierie d'états quantiques multimodes avec des impulsions femtosecondes by
Adrien Dufour(
)
1 edition published in 2018 in French and held by 1 WorldCat member library worldwide
This thesis' purpose is to prepare multimode quantum states with new properties, taking advantage of the frequency combs' capabilities applied to quantum optics. One of those capabilities is their highly multimode nature, which makes us able to generate multimode states, such as the multimode squeezed vacuum generated in our lab with an frequencycombpumped OPO. In order to control the way the squeezed vacua spread over the modes of the comb, we performed the spectral pulse shaping of the pump beam. We show that multimode homodyne detection is an essential analysis tool and pave the way for its implementation. With a set of given modes, it is also possible to alter the quantum state itself. Specifically, the Wigner function can be made nongaussian by a photon subtraction. We applied the multimode photon subtraction and we generated for the first time a multimode photonsubtracted squeezed vacuum with more than 2 modes. We report negativity of the Wigner function. Our photon subtraction scheme is mode selective, which allowed us to subtract in a coherent superposition of modes. We applied it on cluster states (highly entangled multimode states), creating states than exhibit inherent entanglement : entanglement that can not be unknotted by a linear transformation such as a change of basis
1 edition published in 2018 in French and held by 1 WorldCat member library worldwide
This thesis' purpose is to prepare multimode quantum states with new properties, taking advantage of the frequency combs' capabilities applied to quantum optics. One of those capabilities is their highly multimode nature, which makes us able to generate multimode states, such as the multimode squeezed vacuum generated in our lab with an frequencycombpumped OPO. In order to control the way the squeezed vacua spread over the modes of the comb, we performed the spectral pulse shaping of the pump beam. We show that multimode homodyne detection is an essential analysis tool and pave the way for its implementation. With a set of given modes, it is also possible to alter the quantum state itself. Specifically, the Wigner function can be made nongaussian by a photon subtraction. We applied the multimode photon subtraction and we generated for the first time a multimode photonsubtracted squeezed vacuum with more than 2 modes. We report negativity of the Wigner function. Our photon subtraction scheme is mode selective, which allowed us to subtract in a coherent superposition of modes. We applied it on cluster states (highly entangled multimode states), creating states than exhibit inherent entanglement : entanglement that can not be unknotted by a linear transformation such as a change of basis
Des atomes froids pour sonder et manipuler des photons piégés by
Dorian Grosso(
)
1 edition published in 2017 in French and held by 1 WorldCat member library worldwide
Mon travail porte sur la construction d'une expérience d'électrodynamique quantique en cavité visant à réaliser un long temps d'interaction entre des atomes, portés dans des états de Rydberg circulaires, et des photons confinés dans une cavité microonde supraconductrice. Une source d'atomes froids génère un jet vertical d'atomes lents, traversant le mode de la cavité, avec une vitesse moyenne de 12 m.s⁻¹. Ainsi, nous obtenons un temps d'interaction atomechamp de l'ordre de la milliseconde. Il devrait permettre, en particulier, l'implémentation de l'effet Zénon quantique dynamique (QZD) sur le champ. Cette dynamique nonclassique est un outil puissant, permettant la manipulation cohérente de l'état du champ et la synthèse de superpositions arbitraires d'états quasiclassiques de Glauber. Sa mise en œuvre nécessite une perturbation, faisant office de mesure, affectant seulement la cavité quand elle contient un nombre de photons n₀ choisi. Nous mettrons à profit le long temps d'interaction dont nous disposons afin de résoudre le spectre des états de l'atome habillés par le champ. L'anharmonicité du spectre visàvis du nombre de photons permet une mesure sélective sur l'état de Fock n₀. Nous décrivons dans ce travail les premiers résultats expérimentaux attestant notre capacité à obtenir un long temps d'interaction. Nous présentons des données spectroscopiques résolvant les transitions associées aux états habillés correspondant à des nombres de photons allant de zéro à quatre et ce pour divers états du champ. Nous quantifions la sélection du nombre de photons obtenue à partir de telles mesures. Ces résultats ouvrent la voie à l'implémentation de la dynamique de Zénon
1 edition published in 2017 in French and held by 1 WorldCat member library worldwide
Mon travail porte sur la construction d'une expérience d'électrodynamique quantique en cavité visant à réaliser un long temps d'interaction entre des atomes, portés dans des états de Rydberg circulaires, et des photons confinés dans une cavité microonde supraconductrice. Une source d'atomes froids génère un jet vertical d'atomes lents, traversant le mode de la cavité, avec une vitesse moyenne de 12 m.s⁻¹. Ainsi, nous obtenons un temps d'interaction atomechamp de l'ordre de la milliseconde. Il devrait permettre, en particulier, l'implémentation de l'effet Zénon quantique dynamique (QZD) sur le champ. Cette dynamique nonclassique est un outil puissant, permettant la manipulation cohérente de l'état du champ et la synthèse de superpositions arbitraires d'états quasiclassiques de Glauber. Sa mise en œuvre nécessite une perturbation, faisant office de mesure, affectant seulement la cavité quand elle contient un nombre de photons n₀ choisi. Nous mettrons à profit le long temps d'interaction dont nous disposons afin de résoudre le spectre des états de l'atome habillés par le champ. L'anharmonicité du spectre visàvis du nombre de photons permet une mesure sélective sur l'état de Fock n₀. Nous décrivons dans ce travail les premiers résultats expérimentaux attestant notre capacité à obtenir un long temps d'interaction. Nous présentons des données spectroscopiques résolvant les transitions associées aux états habillés correspondant à des nombres de photons allant de zéro à quatre et ce pour divers états du champ. Nous quantifions la sélection du nombre de photons obtenue à partir de telles mesures. Ces résultats ouvrent la voie à l'implémentation de la dynamique de Zénon
High sensitivity matterwave interferometry : towards a determination of the fine structure constant below 1010 by
Léo Morel(
)
1 edition published in 2019 in English and held by 1 WorldCat member library worldwide
The fine structure constant can be determined from the measurement of the ratio h/m between the Planck constant, h, and the mass of an atom, m. The comparison of the experimental value of the anomalous magnetic moment of the electron or the muon with their theoretical values predicted by the Standard Model using this value of the fine structure constant allows a very precise test of this model. My thesis work focused principally on the measurement of the h/m ratio of rubidium87 using a new experimental device. This device has been designed to produce an ultracold source by evaporation in an alloptical dipole trap loaded from optical molasses. We optimized the parameters of the experimental device using a genetic algorithm, which allowed us to produce a Bose Einstein condensate, containing 120,000 atoms, polarized in the state F=1, mF=0, with a cycle time of 3.5 seconds. We then installed the laser device for atom interferometry, to interrogate a cloud of cold atoms produced by optical molasses. Combining an interferometer using Raman transitions and the Bloch oscillation technique, we demonstrated an unprecedented sensitivity on the measurement of h/m corresponding to a relative statistical uncertainty of 8.5 x 1011 in 48 hours of integration, or 4.3 x 1011 on the fine structure constant. This sensitivity has allowed us to experimentally study a variety of systematic effects. We simultaneously carried out modelling work that contributed to the implementation of protocols to compensate for the biases induced by systematic effects. We present a preliminary assessment of the error budget associated with these effects
1 edition published in 2019 in English and held by 1 WorldCat member library worldwide
The fine structure constant can be determined from the measurement of the ratio h/m between the Planck constant, h, and the mass of an atom, m. The comparison of the experimental value of the anomalous magnetic moment of the electron or the muon with their theoretical values predicted by the Standard Model using this value of the fine structure constant allows a very precise test of this model. My thesis work focused principally on the measurement of the h/m ratio of rubidium87 using a new experimental device. This device has been designed to produce an ultracold source by evaporation in an alloptical dipole trap loaded from optical molasses. We optimized the parameters of the experimental device using a genetic algorithm, which allowed us to produce a Bose Einstein condensate, containing 120,000 atoms, polarized in the state F=1, mF=0, with a cycle time of 3.5 seconds. We then installed the laser device for atom interferometry, to interrogate a cloud of cold atoms produced by optical molasses. Combining an interferometer using Raman transitions and the Bloch oscillation technique, we demonstrated an unprecedented sensitivity on the measurement of h/m corresponding to a relative statistical uncertainty of 8.5 x 1011 in 48 hours of integration, or 4.3 x 1011 on the fine structure constant. This sensitivity has allowed us to experimentally study a variety of systematic effects. We simultaneously carried out modelling work that contributed to the implementation of protocols to compensate for the biases induced by systematic effects. We present a preliminary assessment of the error budget associated with these effects
Soustracteur de photons uniques pour états quantiques multimode dans le domaine spectral by
Clément Jacquard(
)
1 edition published in 2017 in English and held by 1 WorldCat member library worldwide
Dans le cadre de cette thèse, nous avons construit et caractérisé un soustracteur de photons uniques pour l'ingénierie d'états quantiques de la lumière. Le but étant de réaliser une soustraction de photon pure et spectralement sélective sur une ressource multimode dans le domaine spectral. Ce soustracteur repose sur une interaction paramétrique de somme de fréquence entre un faisceau signal et un faisceau de contrôle au sein d'un milieu nonlinéaire. Le spectre du faisceau de contrôle est mis en forme à l'aide d'un procédé de mise en forme d'impulsion. Le photon convertit est filtré et détecté grâce à détecteur de photon unique. Le soustracteur est donc la combinaison de tous ces éléments successifs. Nous avons développé un cadre théorique décrivant la soustraction multimode de photons uniques et montré qu'elle peut être décrite, peu importe l'implémentation, par une matrice de soustraction dans une base de modes. Grâce à ce formalisme, nous avons montré que le processus pouvait être caractérisé sans mesurer le signal transformé mais simplement en lui substituant un faisceau sonde dont les impulsions sont aussi mises en forme. Nous avons réalisé une tomographie du processus au niveau du photon unique pour une large gamme de faisceaux de contrôle différents. Nos résultats sont correctement décrits par la théorie développée et démontre la pureté du processus ainsi que l'agilité de la technique employée
1 edition published in 2017 in English and held by 1 WorldCat member library worldwide
Dans le cadre de cette thèse, nous avons construit et caractérisé un soustracteur de photons uniques pour l'ingénierie d'états quantiques de la lumière. Le but étant de réaliser une soustraction de photon pure et spectralement sélective sur une ressource multimode dans le domaine spectral. Ce soustracteur repose sur une interaction paramétrique de somme de fréquence entre un faisceau signal et un faisceau de contrôle au sein d'un milieu nonlinéaire. Le spectre du faisceau de contrôle est mis en forme à l'aide d'un procédé de mise en forme d'impulsion. Le photon convertit est filtré et détecté grâce à détecteur de photon unique. Le soustracteur est donc la combinaison de tous ces éléments successifs. Nous avons développé un cadre théorique décrivant la soustraction multimode de photons uniques et montré qu'elle peut être décrite, peu importe l'implémentation, par une matrice de soustraction dans une base de modes. Grâce à ce formalisme, nous avons montré que le processus pouvait être caractérisé sans mesurer le signal transformé mais simplement en lui substituant un faisceau sonde dont les impulsions sont aussi mises en forme. Nous avons réalisé une tomographie du processus au niveau du photon unique pour une large gamme de faisceaux de contrôle différents. Nos résultats sont correctement décrits par la théorie développée et démontre la pureté du processus ainsi que l'agilité de la technique employée
Métrologie de la fréquence de transition 1S3S dans l'hydrogène : contribution au débat sur le rayon de charge du proton by
Hélène Fleurbaey(
)
1 edition published in 2017 in English and held by 1 WorldCat member library worldwide
The precise measurement of the 1S3S transition frequency of hydrogen could have a great impact on the proton charge radius puzzle, which results from the recent spectroscopy of muonic hydrogen. In our experiment, the twophoton 1S3S transition is excited in a hydrogen atomic beam, with a continuouswave 205nm laser which is obtained by sum frequency generation in a nonlinear crystal. The transition frequency is measured with respect to the LNESYRTE Cs clock by means of a frequency comb. Recording the signal for several values of an applied magnetic field allows to estimate the velocity distribution of the atoms in the beam and deduce the secondorder Doppler shift. Other frequencyshifting systematic effects have been taken into account: crossdamping, light shift, collisions. A complete study has shown that the velocity distribution does not depend significantly on the pressure, and allowed to determine the collisional shift. Eventually, a value of the 1S3S transition frequency is obtained with an uncertainty of about 5 kHz, or a relative uncertainty of 1.7 10^12. It is in very good agreement with the CODATA recommended value. This new measurement contributes to the ongoing search to solve the proton radius puzzle
1 edition published in 2017 in English and held by 1 WorldCat member library worldwide
The precise measurement of the 1S3S transition frequency of hydrogen could have a great impact on the proton charge radius puzzle, which results from the recent spectroscopy of muonic hydrogen. In our experiment, the twophoton 1S3S transition is excited in a hydrogen atomic beam, with a continuouswave 205nm laser which is obtained by sum frequency generation in a nonlinear crystal. The transition frequency is measured with respect to the LNESYRTE Cs clock by means of a frequency comb. Recording the signal for several values of an applied magnetic field allows to estimate the velocity distribution of the atoms in the beam and deduce the secondorder Doppler shift. Other frequencyshifting systematic effects have been taken into account: crossdamping, light shift, collisions. A complete study has shown that the velocity distribution does not depend significantly on the pressure, and allowed to determine the collisional shift. Eventually, a value of the 1S3S transition frequency is obtained with an uncertainty of about 5 kHz, or a relative uncertainty of 1.7 10^12. It is in very good agreement with the CODATA recommended value. This new measurement contributes to the ongoing search to solve the proton radius puzzle
Dispositifs hybrides : nanoparticules couplées à une nanofibre optique by
Maxime Joos(
)
1 edition published in 2018 in French and held by 1 WorldCat member library worldwide
In this thesis, we present an experimental study of hybrid systems where nanoemitters are coupled to optical nanofibers. The strong transverse confinement of light in subwavelength fibres implies an “exotic” electric field (longitudinal electric field component, inhomogeneous polarisation etc.) that we use in order to alter the radiation properties of nanoemitter placed at the surface of the nanofiber. Based on the same system : nanoparticle + nanofibre, we developped an “optical ruler” to localise the nanofiber with nanometer precision. This open the way to the study of nanofibre optomechanics
1 edition published in 2018 in French and held by 1 WorldCat member library worldwide
In this thesis, we present an experimental study of hybrid systems where nanoemitters are coupled to optical nanofibers. The strong transverse confinement of light in subwavelength fibres implies an “exotic” electric field (longitudinal electric field component, inhomogeneous polarisation etc.) that we use in order to alter the radiation properties of nanoemitter placed at the surface of the nanofiber. Based on the same system : nanoparticle + nanofibre, we developped an “optical ruler” to localise the nanofiber with nanometer precision. This open the way to the study of nanofibre optomechanics
Quantum optics with single collective excitations of nanofibertrapped arrays of atoms by
Jérémy Raskop(
)
1 edition published in 2020 in English and held by 1 WorldCat member library worldwide
This thesis focuses on the study of interactions between photons guided by an optical nanofiber and arrays of trapped atoms. Our experimental setup consists in a twocolor compensated dipole trap located in the evanescent field of an optical nanofiber in a ultrahigh vacuum chamber. Cold cesium atoms are trapped in two 1D arrays above and below the nanofiber. An optical depth of over 130 is achieved with only a few thousand atoms. We demonstrate the ability to prepare the trapped atoms in a single Zeeman sublevel, albeit with limited efficiency. This is an important step towards the realization of a longlived quantum memory with our fibered platform. The main result of this thesis concerns the initialization of a single collective excitation coupled to the nanowaveguide. The excitation is heralded by the detection of a Raman scattered photon in the nanofiber. We are then able to readout the atomic state and retrieve a single photon in the guided mode with an efficiency of up to 25%. This result is the first demonstration of an atomic entangled state preferentially coupled to a waveguide. It is a milestone in the context of the emerging waveguideQED approach, with applications to quantum networking, quantum nonlinear optics and quantum manybody physics
1 edition published in 2020 in English and held by 1 WorldCat member library worldwide
This thesis focuses on the study of interactions between photons guided by an optical nanofiber and arrays of trapped atoms. Our experimental setup consists in a twocolor compensated dipole trap located in the evanescent field of an optical nanofiber in a ultrahigh vacuum chamber. Cold cesium atoms are trapped in two 1D arrays above and below the nanofiber. An optical depth of over 130 is achieved with only a few thousand atoms. We demonstrate the ability to prepare the trapped atoms in a single Zeeman sublevel, albeit with limited efficiency. This is an important step towards the realization of a longlived quantum memory with our fibered platform. The main result of this thesis concerns the initialization of a single collective excitation coupled to the nanowaveguide. The excitation is heralded by the detection of a Raman scattered photon in the nanofiber. We are then able to readout the atomic state and retrieve a single photon in the guided mode with an efficiency of up to 25%. This result is the first demonstration of an atomic entangled state preferentially coupled to a waveguide. It is a milestone in the context of the emerging waveguideQED approach, with applications to quantum networking, quantum nonlinear optics and quantum manybody physics
Développement expérimental d'un capteur inertiel multiaxe à atomes froids hybride embarquable by
Isadora Perrin(
)
1 edition published in 2019 in French and held by 1 WorldCat member library worldwide
This work focuses on the development of a coldatom inertial sensor measuring the gravity, the vertical gravity gradient and the horizontal acceleration, by choosing technologies enabling to obtain an onboard and hybrid inertial sensor. The experimental setup generates a cold atom cloud of 87Rb, allows vertical et horizontal interferometry sequences using retroreflected contrapropagating stimulated Raman transitions, and allows a maximum free fall distance of 20 cm. The sensitivity obtained for the measurement of the gravity is 68 microGal/VHz and the optimal resolution reached 1,4 microGal after 6000 s of integration. The fourpulses interferometry sequence has been used for the measurement of the vertical gravity gradient. The sensitivity and the systematics have been studied. Our measurement, extrapolated with a sensor allowing 1 meter free fall and limited by quantum projection noise, could reach a sensitivity of 13 E/VHz, competitive with state of theart. This method could be used for the measurement of rotations in an onboard inertiel sensor. A measurement of horizontal acceleration using simple diffraction interferometer with horizontal retroreflected contrapropagation stimulated Raman transitions. To lift the degeneracy of the two Raman transitions in the horizontal axis with zerovelocity atoms, we chirp the frequency of the Raman beam. It allows us to realize a MachZehnder atom interferometer to measure the horizontal acceleration
1 edition published in 2019 in French and held by 1 WorldCat member library worldwide
This work focuses on the development of a coldatom inertial sensor measuring the gravity, the vertical gravity gradient and the horizontal acceleration, by choosing technologies enabling to obtain an onboard and hybrid inertial sensor. The experimental setup generates a cold atom cloud of 87Rb, allows vertical et horizontal interferometry sequences using retroreflected contrapropagating stimulated Raman transitions, and allows a maximum free fall distance of 20 cm. The sensitivity obtained for the measurement of the gravity is 68 microGal/VHz and the optimal resolution reached 1,4 microGal after 6000 s of integration. The fourpulses interferometry sequence has been used for the measurement of the vertical gravity gradient. The sensitivity and the systematics have been studied. Our measurement, extrapolated with a sensor allowing 1 meter free fall and limited by quantum projection noise, could reach a sensitivity of 13 E/VHz, competitive with state of theart. This method could be used for the measurement of rotations in an onboard inertiel sensor. A measurement of horizontal acceleration using simple diffraction interferometer with horizontal retroreflected contrapropagation stimulated Raman transitions. To lift the degeneracy of the two Raman transitions in the horizontal axis with zerovelocity atoms, we chirp the frequency of the Raman beam. It allows us to realize a MachZehnder atom interferometer to measure the horizontal acceleration
Electromechanical cooling and parametric amplification of an ultrahighQ mechanical oscillator by
Thibault Capelle(
)
1 edition published in 2020 in English and held by 1 WorldCat member library worldwide
In this thesis, we have studied an ultrahigh quality factor mechanical oscillator coupled to a microwave cavity. We will present an original technique to probe the losses of planar microwave cavities, as well as a resolved sideband cooling technique to actively cool this mechanical oscillator using the microwave cavity. Finally, we will present some optimizations of this experiment which open the path towards the ground state cooling of the mechanical oscillator. Such a hybrid quantum system could be used as an onchip quantum memory, able to store fragile quantum states generated by superconducting quantum circuits for coherence times approaching a second
1 edition published in 2020 in English and held by 1 WorldCat member library worldwide
In this thesis, we have studied an ultrahigh quality factor mechanical oscillator coupled to a microwave cavity. We will present an original technique to probe the losses of planar microwave cavities, as well as a resolved sideband cooling technique to actively cool this mechanical oscillator using the microwave cavity. Finally, we will present some optimizations of this experiment which open the path towards the ground state cooling of the mechanical oscillator. Such a hybrid quantum system could be used as an onchip quantum memory, able to store fragile quantum states generated by superconducting quantum circuits for coherence times approaching a second
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Related Identities
 École doctorale Physique en ÎledeFrance (Paris / 2014....). Other
 Sorbonne université (Paris / 2018....). Degree grantor
 Université Pierre et Marie Curie (Paris / 19712017) Degree grantor
 Maître, Agnès Other Opponent
 Fabre, Claude (1951....; physicien) Opponent Thesis advisor
 Raimond, JeanMichel (1955....). Opponent Thesis advisor
 Treps, Nicolas Thesis advisor
 Laurat, Julien Thesis advisor
 Lamour, Emily Other
 Schwob, Catherine Other
Alternative Names
Centre national de la recherche scientifique (France). Laboratoire Kastler Brossel
CNRS (Paris). UMR 8552
Collège de France. Laboratoire Kastler Brossel (Paris)
Ecole Normale Supérieure Laboratoire Kastler Brossel
École normale supérieure (Paris). Laboratoire Kastler Brossel
ENS (Paris). UMR 8552
Laboratoire Kastler Brossel Forschungsinstitut für Grundlagenforschung im Bereich der Quantenphysik in Paris
LKB
Sorbonne université (Paris). Laboratoire Kastler Brossel
SU (Paris). UMR 8552
UMR 8552
UMR8552
Université Pierre et Marie Curie (Paris). Laboratoire Kastler Brossel
UPMC (Paris). UMR 8552
КаслерБроссел тәҗрибәханәсе
カストレル・ブロッセル研究所
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