Pub Date : 2024-08-06DOI: 10.1103/physreva.110.022804
C. T. Plowman, K. H. Spicer, N. W. Antonio, M. S. Schöffler, M. Schulz, I. Bray, A. S. Kadyrov
We use the two-center wave-packet convergent close-coupling approach to ion-atom collisions to calculate the energy and angular distribution of electrons emitted in proton collisions with atomic hydrogen. Results are provided across a wide range of intermediate energies where many competing reaction channels make calculations challenging. The present data consistently agree with the available experimental measurements and improve upon previously available results based on perturbative and classical methods. Furthermore, we extend the range of electron angles and energies over which theoretical data are available for the doubly differential cross section for ionization. This provides strong evidence that at the level of doubly differential cross sections nonperturbative high-order methods are required to accurately model the ionization process.
{"title":"Doubly differential cross sections for ionization in proton collisions with atomic hydrogen: Energy and angular distribution of emitted electrons","authors":"C. T. Plowman, K. H. Spicer, N. W. Antonio, M. S. Schöffler, M. Schulz, I. Bray, A. S. Kadyrov","doi":"10.1103/physreva.110.022804","DOIUrl":"https://doi.org/10.1103/physreva.110.022804","url":null,"abstract":"We use the two-center wave-packet convergent close-coupling approach to ion-atom collisions to calculate the energy and angular distribution of electrons emitted in proton collisions with atomic hydrogen. Results are provided across a wide range of intermediate energies where many competing reaction channels make calculations challenging. The present data consistently agree with the available experimental measurements and improve upon previously available results based on perturbative and classical methods. Furthermore, we extend the range of electron angles and energies over which theoretical data are available for the doubly differential cross section for ionization. This provides strong evidence that at the level of doubly differential cross sections nonperturbative high-order methods are required to accurately model the ionization process.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1103/physreva.110.023307
Niccolò Preti, Nicolò Antolini, Giulio Biagioni, Andrea Fioretti, Giovanni Modugno, Luca Tanzi, Carlo Gabbanini
Short-wavelength repulsive potentials for quantum gases allow one to realize new systems and to study new phenomena. Here we report the realization of repulsive optical potentials for dysprosium atoms in the blue region of the spectrum, at wavelengths close to 400 nm. We employ a spectrally filtered diode laser system to measure both scalar and tensorial components of the polarizability of dysprosium, which we find in good agreement with the theoretical predictions. We demonstrate the implementation of potential strengths appropriate to manipulate Bose-Einstein condensates, with scattering-limited lifetimes exceeding 1 s. This type of optical potential opens interesting directions for the study of dipolar superfluids and supersolids.
{"title":"Blue repulsive potential for dysprosium Bose-Einstein condensates","authors":"Niccolò Preti, Nicolò Antolini, Giulio Biagioni, Andrea Fioretti, Giovanni Modugno, Luca Tanzi, Carlo Gabbanini","doi":"10.1103/physreva.110.023307","DOIUrl":"https://doi.org/10.1103/physreva.110.023307","url":null,"abstract":"Short-wavelength repulsive potentials for quantum gases allow one to realize new systems and to study new phenomena. Here we report the realization of repulsive optical potentials for dysprosium atoms in the blue region of the spectrum, at wavelengths close to 400 nm. We employ a spectrally filtered diode laser system to measure both scalar and tensorial components of the polarizability of dysprosium, which we find in good agreement with the theoretical predictions. We demonstrate the implementation of potential strengths appropriate to manipulate Bose-Einstein condensates, with scattering-limited lifetimes exceeding 1 s. This type of optical potential opens interesting directions for the study of dipolar superfluids and supersolids.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1103/physreva.110.022604
Adel Ali, Alexey Belyanin
We propose a method to achieve coherent, field-free coupling between the toroidal flux qubit (tfluxon), which is isolated from the environment, and a charged particle on a quantum ring. The resulting nonlocal coupling is mediated only by the vector potential and can be used to control the tfluxon by acting on the quantum ring's degrees of freedom. Furthermore, the emergent coupling can facilitate coherent interaction between states of distant tfluxons mediated by an electron on a quantum ring. We demonstrate that the topological and nonlocal aspects of this system are of fundamental interest and can have important applications in quantum information, benefiting from the decoupling from the environment and the topological protection.
{"title":"Topological nonlocal operations on toroidal flux qubits","authors":"Adel Ali, Alexey Belyanin","doi":"10.1103/physreva.110.022604","DOIUrl":"https://doi.org/10.1103/physreva.110.022604","url":null,"abstract":"We propose a method to achieve coherent, field-free coupling between the toroidal flux qubit (tfluxon), which is isolated from the environment, and a charged particle on a quantum ring. The resulting nonlocal coupling is mediated only by the vector potential and can be used to control the tfluxon by acting on the quantum ring's degrees of freedom. Furthermore, the emergent coupling can facilitate coherent interaction between states of distant tfluxons mediated by an electron on a quantum ring. We demonstrate that the topological and nonlocal aspects of this system are of fundamental interest and can have important applications in quantum information, benefiting from the decoupling from the environment and the topological protection.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1103/physreva.110.022210
Irene Ada Picatoste, Rafael Sánchez
Few-level systems coupled to thermal baths provide useful models for quantum thermodynamics and to understand the role of heat currents in quantum information settings. Useful operations such as cooling or thermal masers have been proposed in autonomous three-level systems. In this work, we propose the coherent coupling of two qutrits as a simultaneous refrigerator and heat pump of two reservoirs forming a system. This occurs thanks to the coupling to two other reservoirs which are out of equilibrium but do not inject heat in the system. We explore the thermodynamic performance of such operation and discuss whether it can be distinguished from the action of a Maxwell demon via measurements of current fluctuations limited to the working substance.
{"title":"All-thermal reversal of heat currents using qutrits","authors":"Irene Ada Picatoste, Rafael Sánchez","doi":"10.1103/physreva.110.022210","DOIUrl":"https://doi.org/10.1103/physreva.110.022210","url":null,"abstract":"Few-level systems coupled to thermal baths provide useful models for quantum thermodynamics and to understand the role of heat currents in quantum information settings. Useful operations such as cooling or thermal masers have been proposed in autonomous three-level systems. In this work, we propose the coherent coupling of two qutrits as a simultaneous refrigerator and heat pump of two reservoirs forming a system. This occurs thanks to the coupling to two other reservoirs which are out of equilibrium but do not inject heat in the system. We explore the thermodynamic performance of such operation and discuss whether it can be distinguished from the action of a Maxwell demon via measurements of current fluctuations limited to the working substance.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1103/physreva.110.022209
Michael J. W. Hall
A simple minimalist argument is given for why some correlations between quantum systems boggle our classical intuition. The argument relies on two elementary physical assumptions, and recovers the standard experimentally testable Bell inequality in a form that applies equally well to correlations between six-sided dice and between photon polarizations. The first assumption, that measurement selection in a first laboratory leaves the measurement statistics in a remote laboratory invariant (no signaling), has been empirically verified, and is shown to be equivalent to the existence of a corresponding joint probability distribution for quantities measured in the first laboratory. The observed violation of the Bell inequality is then equivalent to the failure of a second assumption, that measurement selection in the remote laboratory leaves such a joint distribution invariant. Indeed, the degree of violation lower-bounds the variation of the joint distribution. It directly follows there are just three possible physical mechanisms underlying such violations—action at a distance (superluminality), unavoidable common factors linking measurement choice and distant properties (conspiracy), and intrinsically incompatible physical quantities (complementarity). The argument extends to all Bell inequalities, and is briefly compared with other derivations.
{"title":"Why quantum correlations are shocking","authors":"Michael J. W. Hall","doi":"10.1103/physreva.110.022209","DOIUrl":"https://doi.org/10.1103/physreva.110.022209","url":null,"abstract":"A simple minimalist argument is given for why some correlations between quantum systems boggle our classical intuition. The argument relies on two elementary physical assumptions, and recovers the standard experimentally testable Bell inequality in a form that applies equally well to correlations between six-sided dice and between photon polarizations. The first assumption, that measurement selection in a first laboratory leaves the measurement statistics in a remote laboratory invariant (no signaling), has been empirically verified, and is shown to be equivalent to the existence of a corresponding joint probability distribution for quantities measured in the first laboratory. The observed violation of the Bell inequality is then equivalent to the failure of a second assumption, that measurement selection in the remote laboratory leaves such a joint distribution invariant. Indeed, the degree of violation lower-bounds the variation of the joint distribution. It directly follows there are just three possible physical mechanisms underlying such violations—action at a distance (superluminality), unavoidable common factors linking measurement choice and distant properties (conspiracy), and intrinsically incompatible physical quantities (complementarity). The argument extends to all Bell inequalities, and is briefly compared with other derivations.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1103/physreva.110.023305
M. Larsson, G. Wolschin
Time-dependent Bose-Einstein condensate formation in ultracold atoms is investigated in a nonlinear diffusion model. For constant transport coefficients, the model has been solved analytically. Here, we extend it to include energy-dependent transport coefficients and numerically solve the nonlinear equation. Our results are compared with the earlier analytical model for constant transport coefficients, and with recent deep-quench data for at various scattering lengths. Some nonphysical predictions from the constant-coefficient model are resolved using energy-dependent drift and diffusion.
{"title":"Time-dependent condensate formation in ultracold atoms with energy-dependent transport coefficients","authors":"M. Larsson, G. Wolschin","doi":"10.1103/physreva.110.023305","DOIUrl":"https://doi.org/10.1103/physreva.110.023305","url":null,"abstract":"Time-dependent Bose-Einstein condensate formation in ultracold atoms is investigated in a nonlinear diffusion model. For constant transport coefficients, the model has been solved analytically. Here, we extend it to include energy-dependent transport coefficients and numerically solve the nonlinear equation. Our results are compared with the earlier analytical model for constant transport coefficients, and with recent deep-quench data for <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mmultiscripts><mi mathvariant=\"normal\">K</mi><mprescripts></mprescripts><none></none><mn>39</mn></mmultiscripts></math> at various scattering lengths. Some nonphysical predictions from the constant-coefficient model are resolved using energy-dependent drift and diffusion.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1103/physreva.110.022409
F. E. S. Steinhoff
The states generated by a multiport beam splitter usually display genuine multipartite entanglement between the many spatial modes. Here we investigate the different classes of multipartite entangled states that arise in this practical situation, working within the paradigm of stochastic local operations with classical communication. We highlight three scenarios, one where the multipartite entanglement classes follow a total number hierarchy, another where the various classes follow a nonclassicality degree hierarchy, and a third one that is a combination of the previous two. Moreover, the multipartite entanglement of higher-dimensional versions of Dicke states relates naturally to our results.
{"title":"Multipartite entanglement classes of a multiport beam splitter","authors":"F. E. S. Steinhoff","doi":"10.1103/physreva.110.022409","DOIUrl":"https://doi.org/10.1103/physreva.110.022409","url":null,"abstract":"The states generated by a multiport beam splitter usually display genuine multipartite entanglement between the many spatial modes. Here we investigate the different classes of multipartite entangled states that arise in this practical situation, working within the paradigm of stochastic local operations with classical communication. We highlight three scenarios, one where the multipartite entanglement classes follow a total number hierarchy, another where the various classes follow a nonclassicality degree hierarchy, and a third one that is a combination of the previous two. Moreover, the multipartite entanglement of higher-dimensional versions of Dicke states relates naturally to our results.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1103/physreva.110.023710
C. Drago, J. E. Sipe
We develop a formalism to describe squeezed light with large spectral-temporal correlations. This description is valid in all regimes, but is especially applicable in the long pulse to continuous-wave limit where the photon density at any particular time is small, although the total number of photons can be quite large. Our method relies on the Whittaker-Shannon interpolation formula applied to the joint temporal amplitude of squeezed light, which allows us to “deconstruct” the squeezed state. This provides a local description of the state and its photon statistics, making the underlying physics more transparent than does the use of the Schmidt decomposition. The formalism can easily be extended to more exotic nonclassical states where a Schmidt decomposition is not possible.
{"title":"Deconstructing squeezed light: Schmidt decomposition versus the Whittaker-Shannon interpolation","authors":"C. Drago, J. E. Sipe","doi":"10.1103/physreva.110.023710","DOIUrl":"https://doi.org/10.1103/physreva.110.023710","url":null,"abstract":"We develop a formalism to describe squeezed light with large spectral-temporal correlations. This description is valid in all regimes, but is especially applicable in the long pulse to continuous-wave limit where the photon density at any particular time is small, although the total number of photons can be quite large. Our method relies on the Whittaker-Shannon interpolation formula applied to the joint temporal amplitude of squeezed light, which allows us to “deconstruct” the squeezed state. This provides a local description of the state and its photon statistics, making the underlying physics more transparent than does the use of the Schmidt decomposition. The formalism can easily be extended to more exotic nonclassical states where a Schmidt decomposition is not possible.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a theoretical scheme for generating vortex light bullets (LBs) in a Rydberg atomic system. The stability property and propagation dynamics of vortex LBs with different topological charges are investigated in twisted circular waveguide arrays with a parity-time () symmetry. The numerical solutions of the corresponding nonlinear Schrödinger equation are obtained by the modified square operator method and split-step Fourier method. The longitudinal twist changes the stabilities of six-core vortex LBs and enriches the modulation diversity as the states with the opposite charges degenerate by the introducing of rotation frequency. Specifically, we reveal that the energy exchange between waveguides and media gives rise to the formation of necklace breathers, which is crucial for implementing light storage. These unique characteristics arise from the balance or quasibalance among the rotation frequency, the Rydberg-Rydberg interaction, and the nonequivalent gain/loss distribution along the azimuthal direction. We thus provide examples of robust high-charge vortex LBs and necklace breathers in the Rydberg atomic system with a symmetry.
{"title":"Vortex light bullets in Rydberg atoms trapped in twisted PT-symmetric waveguide arrays","authors":"Siliu Xu, Junhao Li, Yiheng Hou, Jun-Rong He, Zhou Fan, Yuan Zhao, Liangwei Dong","doi":"10.1103/physreva.110.023508","DOIUrl":"https://doi.org/10.1103/physreva.110.023508","url":null,"abstract":"We present a theoretical scheme for generating vortex light bullets (LBs) in a Rydberg atomic system. The stability property and propagation dynamics of vortex LBs with different topological charges are investigated in twisted circular waveguide arrays with a parity-time (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"script\">PT</mi></math>) symmetry. The numerical solutions of the corresponding nonlinear Schrödinger equation are obtained by the modified square operator method and split-step Fourier method. The longitudinal twist changes the stabilities of six-core vortex LBs and enriches the modulation diversity as the states with the opposite charges degenerate by the introducing of rotation frequency. Specifically, we reveal that the energy exchange between waveguides and media gives rise to the formation of necklace breathers, which is crucial for implementing light storage. These unique characteristics arise from the balance or quasibalance among the rotation frequency, the Rydberg-Rydberg interaction, and the nonequivalent gain/loss distribution along the azimuthal direction. We thus provide examples of robust high-charge vortex LBs and necklace breathers in the Rydberg atomic system with a <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"script\">PT</mi></math> symmetry.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1103/physreva.110.023308
Wei Wang, Zheng Zhang, Gui-Xin Tang, Tao Wang
We propose to synthesize tunable periodic gauge fields via Floquet engineering cold-alkaline-earth-metal atoms in one-dimensional optical lattice. The artificial magnetic flux is designed to emerge during the combined process of Floquet photon-assisted tunneling and internal state transitions. By varying the initial phases of the driving protocol, our proposal presents the ability to smoothly tune the periodic flux. Moreover, we demonstrate that the effective two-leg flux ladder model can simulate one typical real topological insulator, which is described by the first Stiefel-Whitney class and protected by the space-inversion–time-reversal symmetry. Benefiting from the long lifetime of excited states of alkaline-earth-metal atoms, our work opens new possibilities for exploiting the physics related to gauge fields, such as topological phases, in the current cold-atom platform.
{"title":"Floquet engineering tunable periodic gauge fields and simulating real topological phases in a cold-alkaline-earth-metal-atom optical lattice","authors":"Wei Wang, Zheng Zhang, Gui-Xin Tang, Tao Wang","doi":"10.1103/physreva.110.023308","DOIUrl":"https://doi.org/10.1103/physreva.110.023308","url":null,"abstract":"We propose to synthesize tunable periodic gauge fields via Floquet engineering cold-alkaline-earth-metal atoms in one-dimensional optical lattice. The artificial magnetic flux is designed to emerge during the combined process of Floquet photon-assisted tunneling and internal state transitions. By varying the initial phases of the driving protocol, our proposal presents the ability to smoothly tune the periodic flux. Moreover, we demonstrate that the effective two-leg flux ladder model can simulate one typical real topological insulator, which is described by the first Stiefel-Whitney class and protected by the space-inversion–time-reversal symmetry. Benefiting from the long lifetime of excited states of alkaline-earth-metal atoms, our work opens new possibilities for exploiting the physics related to gauge fields, such as topological phases, in the current cold-atom platform.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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