Time-dependent Variational Principles for Hybrid Non-Unitary Dynamics: Application to Driven-Dissipative Superconductors
- URL: http://arxiv.org/abs/2510.12737v1
- Date: Tue, 14 Oct 2025 17:13:29 GMT
- Title: Time-dependent Variational Principles for Hybrid Non-Unitary Dynamics: Application to Driven-Dissipative Superconductors
- Authors: Pasquale Filice, Marco Schirò, Giacomo Mazza,
- Abstract summary: We study the non-unitary dynamics of open quantum many-body systems.<n>We show that the non-Hermitian limit acts as a singular limit of the hybrid dissipative dynamics.
- Score: 0.0
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: We introduce time-dependent variational principles to study the non-unitary dynamics of open quantum many-body systems, including dynamics described by the full Lindblad master equation, the non-Hermitian dynamics corresponding to the no-click limit of the fully post-selected quantum trajectories, and the dynamics described by a hybrid Lindbladian with a control parameter $\alpha$ which interpolates between the full post-selection and averaging over all quantum trajectories. As an application we study the non-unitary dynamics of a lossy or driven-dissipative BCS superconductors, evolving in presence of two-body losses and two-body pumps. We show that the non-Hermitian limit acts as a singular limit of the hybrid dissipative dynamics, leading to a sharp modification of the universal approach to the driven-dissipative steady-states. By considering the dissipative dynamics with pair losses, we show that, as the non-Hermitian limit is approached, the density dynamics sharply evolves from a universal power-law to exponential decay that converges towards a quasi-steady plateau characterized by the freezing of the particle depletion due to pair losses. The reached quasi-stationary density increases as a function of the dissipation rate highlighting the emergence of a non-Hermitian Zeno effect in the lossy dynamics. For the driven-dissipative case, we show that, in the non-Hermitian limit, the system gets trapped into an effective negative temperature state, thus skipping the infinite temperature steady-state reached in the presence of finite contribution of the quantum jumps. We rationalize these findings in terms of the conservation of the length of the pseudospins which, in the non-Hermitian limit, suppresses the effective single-particle losses and pumps acting on the non-condensed particles.
Related papers
- Probing emergent prethermal dynamics and resonant melting on a programmable quantum simulator [28.28351393962583]
dynamics of isolated quantum systems following a sudden quench plays a central role in many areas of material science, high-energy physics, and quantum chemistry.<n>Here, we use a programmable neutral atom quantum simulator to explore quench dynamics in spin models with up to 180 qubits.<n>We trace their robustness to Floquet-like prethermal steady states that are stabilized over long emergent timescales.
arXiv Detail & Related papers (2025-10-13T17:58:04Z) - Generalised fractional Rabi problem [35.18016233072556]
Fractional quantum dynamics provides a natural framework to capture nonlocal temporal behavior and memory effects in quantum systems.<n>In this work, we analyze the physical consequences of fractional-order quantum evolution using a Green's function formulation based on the Caputo fractional derivative.<n>We find that even in the absence of external driving, the static Hamiltonian term induces non-trivial spin dynamics with damping features directly linked to the fractional temporal nonlocality.
arXiv Detail & Related papers (2025-10-09T12:51:57Z) - Quantum tunneling and anti-tunneling across entropic barriers [44.99833362998488]
We study the dynamics of a quantum particle in a constricted two-dimensional channel.<n>We analyze how the onset of quantum corrections impacts the (semi-intuitive) high-temperature behaviour, as temperature is lowered.
arXiv Detail & Related papers (2025-05-06T19:55:55Z) - Measurement phase transitions in the no-click limit as quantum phase
transitions of a non-hermitean vacuum [77.34726150561087]
We study phase transitions occurring in the stationary state of the dynamics of integrable many-body non-Hermitian Hamiltonians.
We observe that the entanglement phase transitions occurring in the stationary state have the same nature as that occurring in the vacuum of the non-hermitian Hamiltonian.
arXiv Detail & Related papers (2023-01-18T09:26:02Z) - Reaction-diffusive dynamics of number-conserving dissipative quantum
state preparation [0.0]
We show the emergence of a diffusive regime for the particle and hole density modes at intermediate length- and time-scales.
We also identify processes that limit the diffusive behavior of this mode at the longest length- and time-scales.
Strikingly, we find that these processes lead to a reaction-diffusion dynamics governed by the Fisher-Kolmogorov-Petrovsky-Piskunov equation.
arXiv Detail & Related papers (2023-01-12T19:11:04Z) - 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) - A dynamical theory for one-dimensional fermions with strong two-body
losses: universal non-Hermitian Zeno physics and spin-charge separation [0.0]
We study an interacting one-dimensional gas of spin-1/2 fermions with two-body losses.
We show how the two non-equilibrium evolutions build up drastically different charge correlations.
arXiv Detail & Related papers (2022-06-14T13:31:33Z) - Decimation technique for open quantum systems: a case study with
driven-dissipative bosonic chains [62.997667081978825]
Unavoidable coupling of quantum systems to external degrees of freedom leads to dissipative (non-unitary) dynamics.
We introduce a method to deal with these systems based on the calculation of (dissipative) lattice Green's function.
We illustrate the power of this method with several examples of driven-dissipative bosonic chains of increasing complexity.
arXiv Detail & Related papers (2022-02-15T19:00:09Z) - Quantum critical systems with dissipative boundaries [0.0]
We study the effects of dissipative boundaries in many-body systems at continuous quantum transitions.
As paradigmatic models, we consider fermionic wires subject to dissipative interactions at the boundaries.
arXiv Detail & Related papers (2021-06-04T15:08:06Z) - Glassy quantum dynamics of disordered Ising spins [0.0]
We study the out-of-equilibrium dynamics in the quantum Ising model with power-law interactions and positional disorder.
Numerically, we confirm that glassy behavior persists for finite system sizes and sufficiently strong disorder.
arXiv Detail & Related papers (2021-04-01T09:08:27Z) - Statistical mechanics of one-dimensional quantum droplets [0.0]
We study the dynamical relaxation process of modulationally unstable one-dimensional quantum droplets.
We find that the instability leads to the spontaneous formation of quantum droplets featuring multiple collisions.
arXiv Detail & Related papers (2021-02-25T15:30:30Z) - Theory of waveguide-QED with moving emitters [68.8204255655161]
We study a system composed by a waveguide and a moving quantum emitter in the single excitation subspace.
We first characterize single-photon scattering off a single moving quantum emitter, showing both nonreciprocal transmission and recoil-induced reduction of the quantum emitter motional energy.
arXiv Detail & Related papers (2020-03-20T12:14:10Z)
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.