Speed limits to fluctuation dynamics

• URL: http://arxiv.org/abs/2309.07301v2
• Date: Wed, 06 Nov 2024 23:40:27 GMT
• Title: Speed limits to fluctuation dynamics
• Authors: Ryusuke Hamazaki,
• Abstract summary: Fluctuation dynamics of an experimentally measured observable offer a primary signal for nonequilibrium systems. We develop a theory concerning rigorous limits to the rate of fluctuation growth. Our results open an avenue toward a quantitative theory of fluctuation dynamics in various non-equilibrium systems.
• Score: 0.0
• License:
• Abstract: Fluctuation dynamics of an experimentally measured observable offer a primary signal for nonequilibrium systems, along with dynamics of the mean. While universal speed limits for the mean have actively been studied recently, constraints for the speed of the fluctuation have been elusive. Here, we develop a theory concerning rigorous limits to the rate of fluctuation growth. We find a principle that the speed of an observable's fluctuation is upper bounded by the fluctuation of an appropriate observable describing velocity, which also indicates a tradeoff relation between the changes for the mean and fluctuation. We demonstrate the advantages of our inequalities for processes with non-negligible dispersion of observables, quantum work extraction, and the entanglement growth in free fermionic systems. Our results open an avenue toward a quantitative theory of fluctuation dynamics in various non-equilibrium systems encompassing quantum many-body systems and nonlinear population dynamics.

Related papers

• Dephasing-assisted diffusive dynamics in superconducting quantum circuits [14.808613294313902]
  We first demonstrate the diffusive dynamics assisted by controlled dephasing noise in superconducting quantum circuits. We show that dephasing can enhance localization in a superconducting qubit array with quasiperiodic order. By preparing different excitation distributions in the qubit array, we observe that a more localized initial state relaxes to a uniformly distributed mixed state faster with dephasing noise.
  arXiv  Detail & Related papers  (2024-11-23T14:14:36Z)
• Quantum highway: Observation of minimal and maximal speed limits for few and many-body states [19.181412608418608]
  Inspired by the energy-time uncertainty principle, bounds have been demonstrated on the maximal speed at which a quantum state can change. We show that one can test the known quantum speed limits and that modifying a single Hamiltonian parameter allows the observation of the crossover of the different bounds on the dynamics.
  arXiv  Detail & Related papers  (2024-08-21T18:00:07Z)
• Dynamical signatures of non-Markovianity in a dissipative-driven qubit [0.0]
  We investigate signatures of non-Markovianity in the dynamics of a periodically-driven qubit coupled to a bosonic environment. Non-Markovian features are quantified by comparing on an equal footing the predictions from diverse and complementary approaches to quantum dissipation.
  arXiv  Detail & Related papers  (2024-01-17T15:58:50Z)
• Chaotic fluctuations in a universal set of transmon qubit gates [37.69303106863453]
  Transmon qubits arise from the quantization of nonlinear resonators. Fast entangling gates, operating at speeds close to the so-called quantum speed limit, contain transient regimes where the dynamics indeed becomes partially chaotic for just two transmons.
  arXiv  Detail & Related papers  (2023-11-24T16:30:56Z)
• Emergence of fluctuating hydrodynamics in chaotic quantum systems [47.187609203210705]
  macroscopic fluctuation theory (MFT) was recently developed to model the hydrodynamics of fluctuations. We perform large-scale quantum simulations that monitor the full counting statistics of particle-number fluctuations in boson ladders. Our results suggest that large-scale fluctuations of isolated quantum systems display emergent hydrodynamic behavior.
  arXiv  Detail & Related papers  (2023-06-20T11:26:30Z)
• Non-equilibrium quantum probing through linear response [41.94295877935867]
  We study the system's response to unitary perturbations, as well as non-unitary perturbations, affecting the properties of the environment. We show that linear response, combined with a quantum probing approach, can effectively provide valuable quantitative information about the perturbation and characteristics of the environment.
  arXiv  Detail & Related papers  (2023-06-14T13:31:23Z)
• Fundamental speed limits on entanglement dynamics of bipartite quantum systems [0.0]
  We derive the speed limits on entanglement using the relative entropy of entanglement and trace-distance entanglement. We find a lower bound on the time required to generate or degrade a certain amount of entanglement by arbitrary quantum dynamics.
  arXiv  Detail & Related papers  (2023-03-13T18:54:56Z)
• Relative purity, speed of fluctuations, and bounds on equilibration times [0.0]
  We discuss the local equilibration of closed systems using the relative purity. Relative purity is an information-theoretic distinguishability measure. We show that the size of fluctuations depends on the quantum coherences of the initial state.
  arXiv  Detail & Related papers  (2021-08-12T19:28:05Z)
• Unifying Quantum and Classical Speed Limits on Observables [0.0]
  We derive a bound on the speed with which observables of open quantum systems evolve. By isolating the coherent and incoherent contributions to the system dynamics, we derive both lower and upper bounds to the speed of evolution.
  arXiv  Detail & Related papers  (2021-08-09T18:00:08Z)
• Exponentially accelerated approach to stationarity in Markovian open quantum systems through the Mpemba effect [0.0]
  We show that the relaxation dynamics of Markovian open quantum systems can be accelerated exponentially by devising an optimal unitary transformation. This initial "rotation" is engineered in such a way that the state of the quantum system becomes to the slowest decaying dynamical mode. We illustrate our idea by showing how to achieve an exponential speed-up in the convergence to stationarity in Dicke models.
  arXiv  Detail & Related papers  (2021-03-08T19:02:31Z)
• Accelerating Convergence of Replica Exchange Stochastic Gradient MCMC via Variance Reduction [24.794221009364772]
  We study the reduction for a noisy energy estimators variance, which promotes much more effective analysis. We obtain the state-of-the-art results in optimization and uncertainty estimates for synthetic experiments and image data.
  arXiv  Detail & Related papers  (2020-10-02T16:23:35Z)

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.