Weak and ultrastrong coupling limits of the quantum mean force Gibbs state

• URL: http://arxiv.org/abs/2104.12606v2
• Date: Fri, 24 Dec 2021 14:12:59 GMT
• Title: Weak and ultrastrong coupling limits of the quantum mean force Gibbs state
• Authors: J. D. Cresser, J. Anders
• Abstract summary: Non-negligible interactions between system and environment can give rise to an altered state. We derive expressions for this mean force Gibbs state, valid for any system that interacts with a bosonic reservoir. The results shed light on the presence of coherences in the strong coupling regime, and provide key tools for nanoscale thermodynamics investigations.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: The Gibbs state is widely taken to be the equilibrium state of a system in contact with an environment at temperature $T$. However, non-negligible interactions between system and environment can give rise to an altered state. Here we derive general expressions for this mean force Gibbs state, valid for any system that interacts with a bosonic reservoir. First, we derive the state in the weak coupling limit and find that, in general, it maintains coherences with respect to the bare system Hamiltonian. Second, we develop a new expansion method suited to investigate the ultrastrong coupling regime. This allows us to derive the explicit form for the mean force Gibbs state, and we find that it becomes diagonal in the basis set by the system-reservoir interaction instead of the system Hamiltonian. Several examples are discussed including a single qubit, a three-level V-system and two coupled qubits all interacting with bosonic reservoirs. The results shed light on the presence of coherences in the strong coupling regime, and provide key tools for nanoscale thermodynamics investigations.

Related papers

• Quantum systems coupled to environments via mean field interactions [0.0]
  We show that when a quantum system is coupled to an environment in a mean field way, its effective dynamics is governed by a unitary group with a time-dependent Hamiltonian. We show that entanglement within the system state is not changed during the dynamics.
  arXiv  Detail & Related papers  (2024-09-24T08:21:10Z)
• Entanglement of Disjoint Intervals in Dual-Unitary Circuits: Exact Results [49.1574468325115]
  The growth of the entanglement between a disjoint subsystem and its complement after a quantum quench is regarded as a dynamical chaos indicator. We show that for almost all dual unitary circuits the entanglement dynamics agrees with what is expected for chaotic systems. Despite having many conserved charges, charge-conserving dual-unitary circuits are in general not Yang-Baxter integrable.
  arXiv  Detail & Related papers  (2024-08-29T17:45:27Z)
• Third quantization with Hartree approximation for open-system bosonic transport [49.1574468325115]
  We present a self-consistent formalism for solving the open-system bosonic Lindblad equation with weak interactions in the steady state. The 3rd Q with Hartree approximation takes into account the infinite Fock space of bosons while its demand of resource scales manageablely with the system size.
  arXiv  Detail & Related papers  (2024-08-23T15:50:48Z)
• Local Harmonic Approximation to Quantum Mean Force Gibbs State [4.169915659794567]
  When the strength of interaction between a quantum system and bath is non-negligible, the equilibrium state can deviate from the Gibbs state. Here, we obtain an approximate expression for such a mean force Gibbs state for a particle in an arbitrary one dimensional potential, interacting with a bosonic bath.
  arXiv  Detail & Related papers  (2024-01-21T20:56:19Z)
• System-bath entanglement of noninteracting fermionic impurities: Equilibrium, transient, and steady-state regimes [0.0]
  We investigate entanglement between a single fermionic level and a fermionic bath in three distinct thermodynamic regimes. The threshold coupling strength, at which entanglement appears, is shown to strongly depend on the bath bandwidth. A steady-state entanglement is generated for arbitrarily weak system-bath couplings at a certain threshold voltage.
  arXiv  Detail & Related papers  (2023-06-16T08:20:55Z)
• Duality between open systems and closed bilayer systems, and thermofield double states as quantum many-body scars [49.1574468325115]
  We find a duality between open many-body systems governed by the Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) equation. Under this duality, the identity operator on the open system side maps to the thermofield double state. We identify broad classes of many-body open systems with nontrivial explicit eigen operators $Q$ of the Lindbladian superoperator.
  arXiv  Detail & Related papers  (2023-04-06T15:38:53Z)
• Unconditional Wigner-negative mechanical entanglement with linear-and-quadratic optomechanical interactions [62.997667081978825]
  We propose two schemes for generating Wigner-negative entangled states unconditionally in mechanical resonators. We show analytically that both schemes stabilize a Wigner-negative entangled state that combines the entanglement of a two-mode squeezed vacuum with a cubic nonlinearity. We then perform extensive numerical simulations to test the robustness of Wigner-negative entanglement attained by approximate CPE states stabilized in the presence of thermal decoherence.
  arXiv  Detail & Related papers  (2023-02-07T19:00:08Z)
• Pulsed multireservoir engineering for a trapped ion with applications to state synthesis and quantum Otto cycles [68.8204255655161]
  Reservoir engineering is a remarkable task that takes dissipation and decoherence as tools rather than impediments. We develop a collisional model to implement reservoir engineering for the one-dimensional harmonic motion of a trapped ion. Having multiple internal levels, we show that multiple reservoirs can be engineered, allowing for more efficient synthesis of well-known non-classical states of motion.
  arXiv  Detail & Related papers  (2021-11-26T08:32:39Z)
• Open quantum system dynamics and the mean force Gibbs state [0.0]
  Is the system's steady state still the Gibbs state? How may the steady state depend on the interaction details? This overview will be of interest to researchers in the wider fields of quantum thermodynamics, open quantum systems, mesoscopic physics, statistical physics and quantum optics.
  arXiv  Detail & Related papers  (2021-10-04T19:08:50Z)
• Partitioning dysprosium's electronic spin to reveal entanglement in non-classical states [55.41644538483948]
  We report on an experimental study of entanglement in dysprosium's electronic spin. Our findings open up the possibility to engineer novel types of entangled atomic ensembles.
  arXiv  Detail & Related papers  (2021-04-29T15:02:22Z)
• A qubit strongly interacting with a bosonic environment: Geometry of thermal states [0.0]
  Zurek's theory of einselection predicts that the decoherence takes place in the so-called pointer basis under the strong coupling regime. We have postulated that the thermals state in the strong coupling limit is a Gibbs state projected onto the pointer basis.
  arXiv  Detail & Related papers  (2020-10-19T04:08:39Z)

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.