A universal speed limit for spreading of quantum coherence

• URL: http://arxiv.org/abs/2410.08204v2
• Date: Wed, 30 Oct 2024 21:01:26 GMT
• Title: A universal speed limit for spreading of quantum coherence
• Authors: Gevorg Martirosyan, Martin Gazo, Jiří Etrych, Simon M. Fischer, Sebastian J. Morris, Christopher J. Ho, Christoph Eigen, Zoran Hadzibabic,
• Abstract summary: We study condensate formation in an isolated atomic gas that is initially far from equilibrium, in an incoherent low-energy state, and condenses as it relaxes towards equilibrium. We show that the spreading of coherence through the system is initially slower for weaker interactions, and faster for stronger ones, but always eventually reaches the same limit. Our results are relevant for quantum technologies that rely on large-scale coherence, and invite similar measurements in other quantum systems.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Discoveries of fundamental limits for the rates of physical processes, from the speed of light to the Lieb-Robinson bound for information propagation, are conceptual breakthroughs that often challenge our understanding of the underlying physics. Here we observe such a limit for a paradigmatic many-body phenomenon, the spreading of coherence during formation of a weakly interacting Bose-Einstein condensate. We study condensate formation in an isolated homogeneous atomic gas that is initially far from equilibrium, in an incoherent low-energy state, and condenses as it relaxes towards equilibrium. Tuning the inter-atomic interactions that drive condensation, we show that the spreading of coherence through the system is initially slower for weaker interactions, and faster for stronger ones, but always eventually reaches the same limit, where the square of the coherence length grows at a universal rate given by the ratio of Planck's constant and the particle mass. These observations are robust to changes in the initial state, the gas density, and the system size. Our results provide benchmarks for theories of universality far from equilibrium, are relevant for quantum technologies that rely on large-scale coherence, and invite similar measurements in other quantum systems.

Related papers

• Improvement of Speed Limits: Quantum Effect on the Speed in Open Quantum Systems [0.0]
  entropy-based speed limits can be used to estimate the minimum time for evolution. We have combined the knowledge of the entropy-based speed limits with that of the resource theory of asymmetry.
  arXiv  Detail & Related papers  (2024-10-15T13:40:24Z)
• Partial confinement in a quantum-link simulator [25.949731736282295]
  We show that the spin-1 quantum link model provides an excellent platform for exploring partial confinement. We conduct a comprehensive investigation of the physics emerging from partial confinement in both the context of equilibrium and non-equilibrium dynamics. Our work offers a simple and feasible routine for the study of confinement-related physics in the state-of-the-art artificial quantum systems.
  arXiv  Detail & Related papers  (2024-04-28T06:55:08Z)
• Decoherence rate in random Lindblad dynamics [4.535465727794938]
  We study the dynamics of open chaotic quantum systems governed by random Lindblad operators. Our work identifies primary features of decoherence in dissipative quantum chaos.
  arXiv  Detail & Related papers  (2024-02-07T09:50:00Z)
• Indication of critical scaling in time during the relaxation of an open quantum system [34.82692226532414]
  Phase transitions correspond to the singular behavior of physical systems in response to continuous control parameters like temperature or external fields. Near continuous phase transitions, associated with the divergence of a correlation length, universal power-law scaling behavior with critical exponents independent of microscopic system details is found.
  arXiv  Detail & Related papers  (2022-08-10T05:59:14Z)
• Number-conserving solution for dynamical quantum backreaction in a Bose-Einstein condensate [0.0]
  We study the exact dynamical evolution of a Bose-Einstein condensate, experimentally realizable in the ultracold gas laboratory. A force density exerted on the gas particles which is of quantum origin is uniquely identified as the deviation from the classical Eulerian force density.
  arXiv  Detail & Related papers  (2022-06-22T18:38:44Z)
• Formation of robust bound states of interacting microwave photons [148.37607455646454]
  One of the hallmarks of interacting systems is the formation of multi-particle bound states. We develop a high fidelity parameterizable fSim gate that implements the periodic quantum circuit of the spin-1/2 XXZ model. By placing microwave photons in adjacent qubit sites, we study the propagation of these excitations and observe their bound nature for up to 5 photons.
  arXiv  Detail & Related papers  (2022-06-10T17:52:29Z)
• Quantum time dilation in a gravitational field [39.58317527488534]
  We investigate how the superposition principle affects the gravitational time dilation observed by a simple clock. We show that the emission rate of an atom prepared in a coherent superposition of separated wave packets in a gravitational field is different from the emission rate of an atom in a classical mixture of these packets.
  arXiv  Detail & Related papers  (2022-04-22T10:02:21Z)
• Experimental study of decoherence of the two-mode squeezed vacuum state via second harmonic generation [19.5474623165562]
  We report a novel scheme on the study of decoherence of a two-mode squeezed vacuum state via its second harmonic generation signal. Our scheme can directly extract the decoherence of the phase-sensitive quantum correlation $langle hatahatbrangle$ between two entangled modes. This is an experimental study on the decoherence effect of a squeezed vacuum state, which has been rarely investigated.
  arXiv  Detail & Related papers  (2020-12-22T05:38:24Z)
• Quantum speed limits for time evolution of a system subspace [77.34726150561087]
  In the present work, we are concerned not with a single state but with a whole (possibly infinite-dimensional) subspace of the system states that are subject to the Schroedinger evolution. We derive an optimal estimate on the speed of such a subspace evolution that may be viewed as a natural generalization of the Fleming bound.
  arXiv  Detail & Related papers  (2020-11-05T12:13:18Z)
• Quantum coherence and speed limit in the mean-field Dicke model of superradiance [0.0]
  We discuss the quantifying of quantum coherence for the Dicke model of superradiance in the mean-field approximation. We find the single-atom $l_1$-norm of coherence is given by the square root of the normalized average intensity of radiation emitted by the superradiant system.
  arXiv  Detail & Related papers  (2020-07-06T16:35:53Z)
• Universal Error Bound for Constrained Quantum Dynamics [0.0]
  We establish an observable-based error bound for a constrained-dynamics approximation in generic gapped quantum systems. Our work establishes a universal and rigorous result concerning nonequilibrium quantum dynamics.
  arXiv  Detail & Related papers  (2020-01-03T06:25:03Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.