WE derive exact and more general solutions of the two coupled Gross-Pitaevskii equation with suitable parameters by demonstrating two analytical methods. In the first method, equations are analysed and inferred some of their mathematical and physical properties, which are then used to derive the exact stationary solutions. In the second method, we demonstrate the Darboux transformation method and construct exact and more general soliton solutions for the Gross-Pitaevskii equation (NLS equation with external potential term). We have proved that the solutions were more general one by showcasing all kinds of soliton pairs by manoeuvring the parameters suitably.
{"title":"More General Soliton Solution for Vectorial Bose-Einstein Condensate","authors":"P. S. Vinayagam","doi":"arxiv-2408.03082","DOIUrl":"https://doi.org/arxiv-2408.03082","url":null,"abstract":"WE derive exact and more general solutions of the two coupled\u0000Gross-Pitaevskii equation with suitable parameters by demonstrating two\u0000analytical methods. In the first method, equations are analysed and inferred\u0000some of their mathematical and physical properties, which are then used to\u0000derive the exact stationary solutions. In the second method, we demonstrate the\u0000Darboux transformation method and construct exact and more general soliton\u0000solutions for the Gross-Pitaevskii equation (NLS equation with external\u0000potential term). We have proved that the solutions were more general one by\u0000showcasing all kinds of soliton pairs by manoeuvring the parameters suitably.","PeriodicalId":501521,"journal":{"name":"arXiv - PHYS - Quantum Gases","volume":"76 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It has recently been predicted that two-dimensional electron gases possess an anomalous ``tomographic'' transport regime outside of the traditional collisionless and hydrodynamic limits, but an experimental confirmation has been elusive so far. This anomalous regime is marked by the appearance of an odd-even effect in the quasiparticle lifetimes where deformations of the Fermi surface with odd-parity become long-lived in comparison to even-parity ones. In this work, we establish neutral atomic quantum gases as an alternative platform to reveal this new transport regime and demonstrate an odd-even effect in the normal phase of two-component Fermi gases. By diagonalizing the Fermi liquid collision integral, we identify odd-parity modes with anomalously long lifetimes below temperatures $Tleq 0.1 T_F$, which is within the reach of current cold atom experiments. In a marked difference from condensed matter setups, we show that the odd-even effect in neutral gases is widely tunable with interactions along the BCS-BEC crossover and suppressed on the BEC side where the Fermi surface is destroyed. We propose the damping rate of quadrupole oscillations as an experimental signature of the long-lived odd-parity modes. The damping rate is set by the shear viscosity, which for finite trap confinement is dominated by odd-parity modes and thus anomalous enhanced compared to the hydrodynamic limit. Furthermore, a full computation of the shear viscosity within Fermi liquid theory shows that the magnitude of the odd-even effect depends on the particle number and is particularly pronounced in mesoscopic Fermi gases. Our findings suggest that the hydrodynamic behavior of neutral degenerate quantum gases is much richer than previously thought and should include additional long-lived modes.
{"title":"Odd-parity effect and scale-dependent viscosity in atomic quantum gases","authors":"Jeff Maki, Ulf Gran, Johannes Hofmann","doi":"arxiv-2408.02738","DOIUrl":"https://doi.org/arxiv-2408.02738","url":null,"abstract":"It has recently been predicted that two-dimensional electron gases possess an\u0000anomalous ``tomographic'' transport regime outside of the traditional\u0000collisionless and hydrodynamic limits, but an experimental confirmation has\u0000been elusive so far. This anomalous regime is marked by the appearance of an\u0000odd-even effect in the quasiparticle lifetimes where deformations of the Fermi\u0000surface with odd-parity become long-lived in comparison to even-parity ones. In\u0000this work, we establish neutral atomic quantum gases as an alternative platform\u0000to reveal this new transport regime and demonstrate an odd-even effect in the\u0000normal phase of two-component Fermi gases. By diagonalizing the Fermi liquid\u0000collision integral, we identify odd-parity modes with anomalously long\u0000lifetimes below temperatures $Tleq 0.1 T_F$, which is within the reach of\u0000current cold atom experiments. In a marked difference from condensed matter\u0000setups, we show that the odd-even effect in neutral gases is widely tunable\u0000with interactions along the BCS-BEC crossover and suppressed on the BEC side\u0000where the Fermi surface is destroyed. We propose the damping rate of quadrupole\u0000oscillations as an experimental signature of the long-lived odd-parity modes.\u0000The damping rate is set by the shear viscosity, which for finite trap\u0000confinement is dominated by odd-parity modes and thus anomalous enhanced\u0000compared to the hydrodynamic limit. Furthermore, a full computation of the\u0000shear viscosity within Fermi liquid theory shows that the magnitude of the\u0000odd-even effect depends on the particle number and is particularly pronounced\u0000in mesoscopic Fermi gases. Our findings suggest that the hydrodynamic behavior\u0000of neutral degenerate quantum gases is much richer than previously thought and\u0000should include additional long-lived modes.","PeriodicalId":501521,"journal":{"name":"arXiv - PHYS - Quantum Gases","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141944243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. S. Rosa, R. M. Francisco, T. Frederico, G. Krein, M. T. Yamashita
The signature of an unatomic system is revealed by a continuous scale invariance that appears during a progressive dimensional squeezing of a resonantly interacting trimer. The unatomic regime is reached at the dimension $overline D$, which for three identical atoms is found to be $overline D=2.292$ - below this value, the trimer wave function at short distances displays a power-law behaviour. The fingerprint of this crossover is a sharp evolution of the contacts that characterizes the trimer momentum distribution tail.
{"title":"Confinement-induced unatomic trimer states","authors":"D. S. Rosa, R. M. Francisco, T. Frederico, G. Krein, M. T. Yamashita","doi":"arxiv-2408.02362","DOIUrl":"https://doi.org/arxiv-2408.02362","url":null,"abstract":"The signature of an unatomic system is revealed by a continuous scale\u0000invariance that appears during a progressive dimensional squeezing of a\u0000resonantly interacting trimer. The unatomic regime is reached at the dimension\u0000$overline D$, which for three identical atoms is found to be $overline\u0000D=2.292$ - below this value, the trimer wave function at short distances\u0000displays a power-law behaviour. The fingerprint of this crossover is a sharp\u0000evolution of the contacts that characterizes the trimer momentum distribution\u0000tail.","PeriodicalId":501521,"journal":{"name":"arXiv - PHYS - Quantum Gases","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141944244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Simeon Simjanovski, Guillaume Gauthier, Halina Rubinsztein-Dunlop, Matthew T. Reeves, Tyler W. Neely
We study the creation and breakdown of a quantized vortex shear layer forming between a stationary Bose-Einstein condensate and a stirred-in persistent current. Once turbulence is established, we characterize the progressive clustering of the vortices, showing that the cluster number follows a power law decay with time, similar to decaying turbulence in other two-dimensional systems. Numerical study of the system demonstrates good agreement of the experimental data with a point vortex model that includes damping and noise. With increasing vortex number in the computational model, we observe a convergence of the power-law exponent to a fixed value.
{"title":"Shear-Induced Decaying Turbulence in Bose-Einstein Condensates","authors":"Simeon Simjanovski, Guillaume Gauthier, Halina Rubinsztein-Dunlop, Matthew T. Reeves, Tyler W. Neely","doi":"arxiv-2408.02200","DOIUrl":"https://doi.org/arxiv-2408.02200","url":null,"abstract":"We study the creation and breakdown of a quantized vortex shear layer forming\u0000between a stationary Bose-Einstein condensate and a stirred-in persistent\u0000current. Once turbulence is established, we characterize the progressive\u0000clustering of the vortices, showing that the cluster number follows a power law\u0000decay with time, similar to decaying turbulence in other two-dimensional\u0000systems. Numerical study of the system demonstrates good agreement of the\u0000experimental data with a point vortex model that includes damping and noise.\u0000With increasing vortex number in the computational model, we observe a\u0000convergence of the power-law exponent to a fixed value.","PeriodicalId":501521,"journal":{"name":"arXiv - PHYS - Quantum Gases","volume":"168 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141944296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. S. Rosa, T. Frederico, R. M. Francisco, G. Krein, M. T. Yamashita
We address the question of the reliability of the Born-Oppenheimer (BO) approximation for a mass-imbalanced resonant three-body system embedded in noninteger dimensions. We address this question within the problem of a system of currently experimental interest, namely $^7$Li$-^{87}$Rb$_2$. We compare the Efimov scale parameter as well as the wave functions obtained using the BO approximation with those obtained using the Bethe-Peierls boundary condition.
我们探讨了嵌入非整数维的质量不平衡共振三体系统的玻恩-奥本海默（Born-Oppenheimer，BO）近似的可靠性问题。我们在一个目前实验感兴趣的系统（即 $^7$Li$-^{87}$Rb$_2$）中讨论了这个问题。我们比较了埃菲莫夫尺度参数以及用 BO 近似法和 Bethe-Peierls 边界条件得到的波函数。
{"title":"Reliability of the Born-Oppenheimer approximation in noninteger dimensions","authors":"D. S. Rosa, T. Frederico, R. M. Francisco, G. Krein, M. T. Yamashita","doi":"arxiv-2408.01776","DOIUrl":"https://doi.org/arxiv-2408.01776","url":null,"abstract":"We address the question of the reliability of the Born-Oppenheimer (BO)\u0000approximation for a mass-imbalanced resonant three-body system embedded in\u0000noninteger dimensions. We address this question within the problem of a system\u0000of currently experimental interest, namely $^7$Li$-^{87}$Rb$_2$. We compare the\u0000Efimov scale parameter as well as the wave functions obtained using the BO\u0000approximation with those obtained using the Bethe-Peierls boundary condition.","PeriodicalId":501521,"journal":{"name":"arXiv - PHYS - Quantum Gases","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141944245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a theoretical review of the recent progress in nonequilibrium BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover physics. As a paradigmatic example, we consider a strongly interacting driven-dissipative two-component Fermi gas where the nonequilibrium steady state is tuned by adjusting the chemical potential difference between two reservoirs that are coupled with the system. As a powerful theoretical tool to deal with this system, we employ the Schwinger-Keldysh Green's function technique. We systematically evaluate the superfluid transition, as well as the single-particle properties, in the nonequilibrium BCS-BEC crossover region, by adjusting the chemical potential difference between the reservoirs and the strength of an s-wave pairing interaction associated with a Feshbach resonance. In the weak-coupling BCS side, the chemical potential difference is shown to imprint a two-step structure on the particle momentum distribution, leading to an anomalous enhancement of pseudogap, as well as the emergence of exotic Fulde-Ferrell-Larkin-Ovchinnikov-type superfluid instability. Since various nonequilibrium situations have recently been realized in ultracold Fermi gases, the theoretical understanding of nonequilibrium BCS-BEC crossover physics would become increasingly important in this research field.
{"title":"Nonequilibrium BCS-BEC crossover and unconventional FFLO superfluid in a strongly interacting driven-dissipative Fermi gas","authors":"Taira Kawamura, Yoji Ohashi","doi":"arxiv-2408.00446","DOIUrl":"https://doi.org/arxiv-2408.00446","url":null,"abstract":"We present a theoretical review of the recent progress in nonequilibrium BCS\u0000(Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover physics.\u0000As a paradigmatic example, we consider a strongly interacting\u0000driven-dissipative two-component Fermi gas where the nonequilibrium steady\u0000state is tuned by adjusting the chemical potential difference between two\u0000reservoirs that are coupled with the system. As a powerful theoretical tool to\u0000deal with this system, we employ the Schwinger-Keldysh Green's function\u0000technique. We systematically evaluate the superfluid transition, as well as the\u0000single-particle properties, in the nonequilibrium BCS-BEC crossover region, by\u0000adjusting the chemical potential difference between the reservoirs and the\u0000strength of an s-wave pairing interaction associated with a Feshbach resonance.\u0000In the weak-coupling BCS side, the chemical potential difference is shown to\u0000imprint a two-step structure on the particle momentum distribution, leading to\u0000an anomalous enhancement of pseudogap, as well as the emergence of exotic\u0000Fulde-Ferrell-Larkin-Ovchinnikov-type superfluid instability. Since various\u0000nonequilibrium situations have recently been realized in ultracold Fermi gases,\u0000the theoretical understanding of nonequilibrium BCS-BEC crossover physics would\u0000become increasingly important in this research field.","PeriodicalId":501521,"journal":{"name":"arXiv - PHYS - Quantum Gases","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141886628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Multifractality of quantum states plays an important role for understanding numerous complex phenomena observed in different branches of physics. The multifractal properties of the eigenstates allow for charactering various phase transitions. In this work, we perform a thoroughly analysis of the impacts of an excited-state quantum phase transition (ESQPT) on the fractal behavior of both static and dynamical wavefunctions in a ferromagentic spin-$1$ Bose-Einstein condensate (BEC).By studying the features of the fractal dimensions, we show how the multifractality of eigenstates and time evolved state are affected by the presence of ESQPT. Specifically, the underlying ESQPT leads to a strong localization effect, which in turn enables us to use it as an indicator of ESQPT. We verify the ability of the fractal dimensions to probe the occurrence of ESQPT through a detailed scaling analysis. We also discuss how the ESQPT manifests itself in the fractal dimensions of the long-time averaged state. Our findings further confirm that the multifractal analysis is a powerful tool for studying of phase transitions in quantum many-body systems and also hint an potential application of ESQPTs in burgeoning field of state preparation engineering.
{"title":"Multifractality and excited-state quantum phase transition in ferromagnetic spin-$1$ Bose-Einstein condensates","authors":"Zhen-Xia Niu, Qian Wang","doi":"arxiv-2407.20612","DOIUrl":"https://doi.org/arxiv-2407.20612","url":null,"abstract":"Multifractality of quantum states plays an important role for understanding\u0000numerous complex phenomena observed in different branches of physics. The\u0000multifractal properties of the eigenstates allow for charactering various phase\u0000transitions. In this work, we perform a thoroughly analysis of the impacts of\u0000an excited-state quantum phase transition (ESQPT) on the fractal behavior of\u0000both static and dynamical wavefunctions in a ferromagentic spin-$1$\u0000Bose-Einstein condensate (BEC).By studying the features of the fractal\u0000dimensions, we show how the multifractality of eigenstates and time evolved\u0000state are affected by the presence of ESQPT. Specifically, the underlying ESQPT\u0000leads to a strong localization effect, which in turn enables us to use it as an\u0000indicator of ESQPT. We verify the ability of the fractal dimensions to probe\u0000the occurrence of ESQPT through a detailed scaling analysis. We also discuss\u0000how the ESQPT manifests itself in the fractal dimensions of the long-time\u0000averaged state. Our findings further confirm that the multifractal analysis is\u0000a powerful tool for studying of phase transitions in quantum many-body systems\u0000and also hint an potential application of ESQPTs in burgeoning field of state\u0000preparation engineering.","PeriodicalId":501521,"journal":{"name":"arXiv - PHYS - Quantum Gases","volume":"77 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141870146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jeff Maki, Colin J. Dale, Joseph H. Thywissen, Shizhong Zhang
Low-dimensional ultracold gases are created in the laboratory by confining three-dimensional (3D) gases inside highly anisotropic trapping potentials. Such trap geometries not only provide access to simulating one-dimensional (1D) and two-dimensional (2D) physics, but also can be used to study how the system crosses over towards a 3D system in the limit of weak confinement. In this work, we study the signature in radio-frequency (RF) spectroscopy for both the 1D-to-3D and the 2D-to-3D crossovers, in spin-polarized Fermi gases. We solve the two-body scattering T-matrix in the presence of strong harmonic confinement and use it to evaluate the two-body bound state and the RF spectroscopy transfer rate in the high frequency limit, covering both the quasi-low-dimensional and 3D limits. We find that in order to understand the dimensional crossover for spin-polarized Fermi gases with p-wave interactions, one needs to take into account an emergent s-wave interaction.
在实验室中，通过将三维（3D）气体束缚在高度各向异性的阱势中，可以产生低维超冷气体。这种阱势几何不仅可以模拟一维（1D）和二维（2D）物理，还可以用来研究在弱束缚极限下系统如何向三维系统交叉。在本研究中，我们研究了自旋极化费米气体中一维到三维和二维到三维交叉的射频光谱特征。我们求解了强谐波约束下的二体散射 T 矩阵，并利用它评估了高频极限下的二体束缚态和射频光谱转移率，涵盖了准低维和三维极限。我们发现，为了理解具有 p 波相互作用的自旋极化费米气体的维度交叉，需要考虑新出现的 s 波相互作用。
{"title":"Radio-Frequency Spectroscopy and the Dimensional Crossover in Interacting Spin-Polarized Fermi Gases","authors":"Jeff Maki, Colin J. Dale, Joseph H. Thywissen, Shizhong Zhang","doi":"arxiv-2407.21106","DOIUrl":"https://doi.org/arxiv-2407.21106","url":null,"abstract":"Low-dimensional ultracold gases are created in the laboratory by confining\u0000three-dimensional (3D) gases inside highly anisotropic trapping potentials.\u0000Such trap geometries not only provide access to simulating one-dimensional (1D)\u0000and two-dimensional (2D) physics, but also can be used to study how the system\u0000crosses over towards a 3D system in the limit of weak confinement. In this\u0000work, we study the signature in radio-frequency (RF) spectroscopy for both the\u00001D-to-3D and the 2D-to-3D crossovers, in spin-polarized Fermi gases. We solve\u0000the two-body scattering T-matrix in the presence of strong harmonic confinement\u0000and use it to evaluate the two-body bound state and the RF spectroscopy\u0000transfer rate in the high frequency limit, covering both the\u0000quasi-low-dimensional and 3D limits. We find that in order to understand the\u0000dimensional crossover for spin-polarized Fermi gases with p-wave interactions,\u0000one needs to take into account an emergent s-wave interaction.","PeriodicalId":501521,"journal":{"name":"arXiv - PHYS - Quantum Gases","volume":"151 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141870145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marc Nairn, Luigi Giannelli, Giovanna Morigi, Sebastian Slama, Beatriz Olmos, Simon B. Jäger
We study the onset of collective spin-self-organization in a thermal ensemble of driven two-level atoms confined in an optical cavity. The atoms spontaneously form a spin-pattern above a critical driving strength that sets a threshold and is determined by the cavity parameters, the initial temperature, and the transition frequency of the atomic spin. Remarkably, we find that inhomogeneous Doppler broadening facilitates the onset of spin-self-organization. In particular, the threshold is non-monotonic when increasing the spin transition frequency and reaches a minimum when the Doppler broadening is of similar magnitude. This feature emerges due to Doppler-induced resonances. Above the threshold, we find cooperative dynamics of spin, spatial, and momentum degrees of freedom leading to density modulations, fast reduction of kinetic energy, and the emergence of non-thermal states. More broadly, our work demonstrates how broadening can facilitate strong light-matter interactions in many-body systems.
{"title":"Spin-self-organization in an optical cavity facilitated by inhomogeneous broadening","authors":"Marc Nairn, Luigi Giannelli, Giovanna Morigi, Sebastian Slama, Beatriz Olmos, Simon B. Jäger","doi":"arxiv-2407.19706","DOIUrl":"https://doi.org/arxiv-2407.19706","url":null,"abstract":"We study the onset of collective spin-self-organization in a thermal ensemble\u0000of driven two-level atoms confined in an optical cavity. The atoms\u0000spontaneously form a spin-pattern above a critical driving strength that sets a\u0000threshold and is determined by the cavity parameters, the initial temperature,\u0000and the transition frequency of the atomic spin. Remarkably, we find that\u0000inhomogeneous Doppler broadening facilitates the onset of\u0000spin-self-organization. In particular, the threshold is non-monotonic when\u0000increasing the spin transition frequency and reaches a minimum when the Doppler\u0000broadening is of similar magnitude. This feature emerges due to Doppler-induced\u0000resonances. Above the threshold, we find cooperative dynamics of spin, spatial,\u0000and momentum degrees of freedom leading to density modulations, fast reduction\u0000of kinetic energy, and the emergence of non-thermal states. More broadly, our\u0000work demonstrates how broadening can facilitate strong light-matter\u0000interactions in many-body systems.","PeriodicalId":501521,"journal":{"name":"arXiv - PHYS - Quantum Gases","volume":"295 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141870152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nick P. Proukakis, Gerasimos Rigopoulos, Alex Soto
We formulate a generalized self-consistent quantum kinetic theory including thermal fluctuations and stochastic contributions for modelling ultracold Bose gases interacting via a generic long-range interaction. Our generalised equations take the usual form of an effective field theory, separating coherent, low-lying, modes of the system from incoherent, higher-lying, thermal modes. The low-lying modes are described by a stochastic Langevin equation with two explicitly time-dependent collisional terms (corresponding to a dissipative and an energy-correcting contribution) and their corresponding additive and multiplicative stochastic noise terms. By coupling such an equation to an explicitly non-equilibrium gas of incoherent (thermal) particles described by a quantum Boltzmann equation, we thus extend beyond both earlier stochastic approaches (including the full SPGPE) and generalised kinetic models inspired by a two-gas picture (the so-called ZNG formalism) commonly used in the context of short-range interactions, such as those relevant in ultracold alkali atoms. Long-range interactions are further included into our model by the self-consistent addition of a Poisson-like equation for the long-range interaction potential. Our approach leads directly to a self-consistent model for finite-temperature Bose-Einstein condensation in a long-range interacting system within the regime where thermal fluctuations dominate over quantum fluctuations. While such an approach could be of general use for a variety of experimentally-accessible long-range interacting systems, we focus specifically here on the well-studied case of dipolar atomic condensates. In this particular context, we additionally supplement our Keldysh non-equilibrium analysis for fluctuations of the fast (incoherent) modes by a somewhat ad hoc extension of the slow (coherent) modes via the usual route of Bogoliubov-de Gennes equations.
{"title":"Self-Consistent Stochastic Finite-Temperature Modelling: Ultracold Bose Gases with Local (s-wave) and Long-Range (Dipolar) Interactions","authors":"Nick P. Proukakis, Gerasimos Rigopoulos, Alex Soto","doi":"arxiv-2407.20178","DOIUrl":"https://doi.org/arxiv-2407.20178","url":null,"abstract":"We formulate a generalized self-consistent quantum kinetic theory including\u0000thermal fluctuations and stochastic contributions for modelling ultracold Bose\u0000gases interacting via a generic long-range interaction. Our generalised\u0000equations take the usual form of an effective field theory, separating\u0000coherent, low-lying, modes of the system from incoherent, higher-lying, thermal\u0000modes. The low-lying modes are described by a stochastic Langevin equation with\u0000two explicitly time-dependent collisional terms (corresponding to a dissipative\u0000and an energy-correcting contribution) and their corresponding additive and\u0000multiplicative stochastic noise terms. By coupling such an equation to an\u0000explicitly non-equilibrium gas of incoherent (thermal) particles described by a\u0000quantum Boltzmann equation, we thus extend beyond both earlier stochastic\u0000approaches (including the full SPGPE) and generalised kinetic models inspired\u0000by a two-gas picture (the so-called ZNG formalism) commonly used in the context\u0000of short-range interactions, such as those relevant in ultracold alkali atoms.\u0000Long-range interactions are further included into our model by the\u0000self-consistent addition of a Poisson-like equation for the long-range\u0000interaction potential. Our approach leads directly to a self-consistent model\u0000for finite-temperature Bose-Einstein condensation in a long-range interacting\u0000system within the regime where thermal fluctuations dominate over quantum\u0000fluctuations. While such an approach could be of general use for a variety of\u0000experimentally-accessible long-range interacting systems, we focus specifically\u0000here on the well-studied case of dipolar atomic condensates. In this particular\u0000context, we additionally supplement our Keldysh non-equilibrium analysis for\u0000fluctuations of the fast (incoherent) modes by a somewhat ad hoc extension of\u0000the slow (coherent) modes via the usual route of Bogoliubov-de Gennes\u0000equations.","PeriodicalId":501521,"journal":{"name":"arXiv - PHYS - Quantum Gases","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141870148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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