Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of the Korean Physical Society

Time-symmetry breaking in a modulated cold atom system: An ideal mean-field transition

Myoung-Sun Heo, Wonho Jhe

Published Aug 1, 2013• 0 citations
Publisher

Abstract

We realize an ideal mean-field transition of time-translation symmetry in a periodically-driven atomic system. The symmetry in steady-state oscillatory atomic motions spontaneously changes with the total number of atoms due to the interplay between inter-atomic interactions which originate from the attenuation effects in the trapping laser light and thermal fluctuations. A large separation of the time scales governing the transition suppresses the spatial dependence of the system dynamics, leading to a mean-field behavior even close to the transition point.

DOI
10.3938/jkps.63.858

Related papers

Spontaneous time‐symmetry breaking in a vibrating cold atom system

Myoung-Sun Heo, Y. Kim, Heung‐Ryoul Noh +1 more

This chapter describes the experimental and theoretical studies of a spontaneous time-translation symmetry breaking transition in a non-equilibrium cold atom system. Such studies prepare two vibrating atomic clouds by periodically modulating the laser intensity in a magneto-optical trap (MOT). For a comparatively small total number of trapped atoms the clouds have equal populations, a consequence of fluctuation-induced inter-cloud transitions. As the total number of atoms is increased, spontaneous breaking of the discrete time-translation symmetry is observed with respect to the modulation period. The measured critical exponents and the frequency dispersion of the response show an ideal mean-field transition behaviour. The symmetry breaking is due to the modification of fluctuational dynamics by the interatomic interaction. The chapter provides a theoretical model based on the activation energy and master equation which explains the experimental results well. The enhancement of the fluctuation which cannot be described by the mean-field model, is also discussed.

Oxford University Press eBooks•Jul 26, 2012•0 citations

Ideal mean-field transition in a modulated cold atom system

Myoung-Sun Heo, Yong Hee Kim, Kihwan Kim +5 more

We show that an atomic system in a periodically modulated optical trap displays an ideal mean-field symmetry-breaking transition. The symmetry is broken with respect to time translation by the modulation period. We describe experimental observations and develop a full microscopic theory of the observed critical phenomena. The transition is explained as resulting from the interplay of the long-range interatomic interaction and nonequilibrium fluctuations in the strongly modulated system. The observations, including anomalous fluctuations in the symmetry broken phase, are fully described by the theory.

arXiv:1001.0749•Physical Review E•Sep 24, 2010•38 citations

Spontaneous breaking of time translation symmetry in a system without periodic external driving

T. T. Sergeev, A. A. Zyablovsky, Evgenii S. Andrianov +1 more

It is known that the spontaneous time translation symmetry breaking can occur in systems periodically driven at a certain period. We predict a spontaneous breaking of time translation symmetry in an atom-cavity system without external driving, in which a time scale is determined by the time of light bypass of the resonator. We demonstrate that there is a parameter range, in which a system state returns to its initial state only after two bypasses of the resonator. We believe that the predicted phenomenon opens a way to a new direction in the time crystal field.

arXiv:2401.08824•Jan 16, 2024•0 citations

Spontaneous breaking of time translation symmetry in a system without periodic external driving

Timofey T. Sergeev, A. A. Zyablovsky, E. S. Andrianov +1 more

It is known that spontaneous time translation symmetry-breaking can occur in systems periodically driven at a certain period. We predict a spontaneous breaking of time translation symmetry in an atom-cavity system without external driving, in which a time scale is determined by the time of light bypass of the resonator. We demonstrate that there is a parameter range, in which a system state returns to its initial state only after two bypasses of the resonator. We believe that the predicted phenomenon opens a way to a new direction in the time crystal field.

Optics Letters•Jul 31, 2024•2 citations

Spontaneous Symmetry Breaking of Population in a Nonadiabatically Driven Atomic Trap: An Ising-Class Phase Transition

Kihwan Kim, Myoung-Sun Heo, Ki-Hwan Lee +4 more

We have observed spontaneous symmetry breaking of the population of Brownian particles between two moving potentials in the spatiotemporally symmetric system. Cold atoms preferentially occupy one of the dynamic double-well potentials, produced in the parametrically driven dissipative magneto-optical trap far from equilibrium, above a critical number of atoms. We find that the population asymmetry, which may be interpreted as the biased Brownian motion, can be qualitatively described by the mean-field Ising-class phase transition. This in situ study may be useful for investigation of dynamic phase transition or temporal behavior of critical phenomena.

arXiv:physics/0507041•Physical Review Letters•Apr 19, 2006•50 citations

Spontaneous emergence of temporal structures in a continuously driven many-body system

Tingmei Li, Hong-Xia Li, Yu-Hui Chen +1 more

Abstract The spontaneous emergence of temporal structures challenges the conventional understanding that systems governed by time-invariant laws remain unchanged over time. Recent experiments have observed this time translation symmetry breaking in quantum atomic systems that either exhibit strong atom-atom interactions or have low dissipation rates. While current theoretical frameworks reveal the importance of strong atom-atom interactions, they fall short in explaining this phenomenon observed in low-dissipation atomic systems. Here, we present a theoretical study on the spontaneous breaking of time translation symmetry in materials with low dissipation rates. By constructing phase diagrams for a system of four-level atoms driven by a continuous-wave optical field, we identify the essential requirements for self-sustained temporal motions. These include a driven open system, nonlinear interactions, and sufficient degrees of freedom that facilitate competing processes. Our findings contribute to a better understanding of the emergence of spontaneous time translation symmetry breaking in these materials.

Europhysics Letters (EPL)•Aug 12, 2024•4 citations
We realize an ideal mean-field transition of time-translation symmetry in a periodically-driven atomic system. The symmetry in steady-state oscillatory atomic motions spontaneously changes with the total number of atoms due to the interplay between inter-atomic interactions which originate from the attenuation effects in the trapping laser light and thermal fluctuations. A large separation of the time scales governing the transition suppresses the spatial dependence of the system dynamics, leading to a mean-field behavior even close to the transition point.
This chapter describes the experimental and theoretical studies of a spontaneous time-translation symmetry breaking transition in a non-equilibrium cold atom system. Such studies prepare two vibrating atomic clouds by periodically modulating the laser intensity in a magneto-optical trap (MOT). For a comparatively small total number of trapped atoms the clouds have equal populations, a consequence of fluctuation-induced inter-cloud transitions. As the total number of atoms is increased, spontaneous breaking of the discrete time-translation symmetry is observed with respect to the modulation period. The measured critical exponents and the frequency dispersion of the response show an ideal mean-field transition behaviour. The symmetry breaking is due to the modification of fluctuational dynamics by the interatomic interaction. The chapter provides a theoretical model based on the activation energy and master equation which explains the experimental results well. The enhancement of the fluctuation which cannot be described by the mean-field model, is also discussed.
We show that an atomic system in a periodically modulated optical trap displays an ideal mean-field symmetry-breaking transition. The symmetry is broken with respect to time translation by the modulation period. We describe experimental observations and develop a full microscopic theory of the observed critical phenomena. The transition is explained as resulting from the interplay of the long-range interatomic interaction and nonequilibrium fluctuations in the strongly modulated system. The observations, including anomalous fluctuations in the symmetry broken phase, are fully described by the theory.
It is known that the spontaneous time translation symmetry breaking can occur in systems periodically driven at a certain period. We predict a spontaneous breaking of time translation symmetry in an atom-cavity system without external driving, in which a time scale is determined by the time of light bypass of the resonator. We demonstrate that there is a parameter range, in which a system state returns to its initial state only after two bypasses of the resonator. We believe that the predicted phenomenon opens a way to a new direction in the time crystal field.
It is known that spontaneous time translation symmetry-breaking can occur in systems periodically driven at a certain period. We predict a spontaneous breaking of time translation symmetry in an atom-cavity system without external driving, in which a time scale is determined by the time of light bypass of the resonator. We demonstrate that there is a parameter range, in which a system state returns to its initial state only after two bypasses of the resonator. We believe that the predicted phenomenon opens a way to a new direction in the time crystal field.
We have observed spontaneous symmetry breaking of the population of Brownian particles between two moving potentials in the spatiotemporally symmetric system. Cold atoms preferentially occupy one of the dynamic double-well potentials, produced in the parametrically driven dissipative magneto-optical trap far from equilibrium, above a critical number of atoms. We find that the population asymmetry, which may be interpreted as the biased Brownian motion, can be qualitatively described by the mean-field Ising-class phase transition. This in situ study may be useful for investigation of dynamic phase transition or temporal behavior of critical phenomena.
Abstract The spontaneous emergence of temporal structures challenges the conventional understanding that systems governed by time-invariant laws remain unchanged over time. Recent experiments have observed this time translation symmetry breaking in quantum atomic systems that either exhibit strong atom-atom interactions or have low dissipation rates. While current theoretical frameworks reveal the importance of strong atom-atom interactions, they fall short in explaining this phenomenon observed in low-dissipation atomic systems. Here, we present a theoretical study on the spontaneous breaking of time translation symmetry in materials with low dissipation rates. By constructing phase diagrams for a system of four-level atoms driven by a continuous-wave optical field, we identify the essential requirements for self-sustained temporal motions. These include a driven open system, nonlinear interactions, and sufficient degrees of freedom that facilitate competing processes. Our findings contribute to a better understanding of the emergence of spontaneous time translation symmetry breaking in these materials.