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

arXiv:2008.03307 · Quantum

Shortcuts to Squeezed Thermal States

Léonce Dupays, Aurélia Chenu

Published May 1, 2021• 18 citations
arXivHTMLPDF

Abstract

Squeezed state in harmonic systems can be generated through a variety of techniques, including varying the oscillator frequency or using nonlinear two-photon Raman interaction. We focus on these two techniques to drive an initial thermal state into a final squeezed thermal state with controlled squeezing parameters – amplitude and phase – in arbitrary time. The protocols are designed through reverse engineering for both unitary and open dynamics. Control of the dissipation is achieved using stochastic processes, readily implementable via, e.g., continuous quantum measurements. Importantly, this allows controlling the state entropy and can be used for fast thermalization. The developed protocols are thus suited to generate squeezed thermal states at controlled temperature in arbitrary time.

DOI
10.22331/q-2021-05-01-449

Related papers

Dynamical engineering of squeezed thermal states

Léonce Dupays, Aurélia Chenu

Control protocols known as shortcuts to adiabaticity allow to drive a quantum system from an initial to a final state arbitrarily fast. These techniques have recently been proposed for open quantum systems, thus extending their application to allow for fast thermalization. Here, we engineer dynamical schemes for the fast preparation of squeezed thermal states at controlled temperature. We derive the equations of motion of squeezed thermal states in harmonic oscillators under unitary and open dynamics, allowing for temperature and entropy variations between the initial and final states. The counter-diabatic Hamiltonians and associated dissipators are provided, and whenever possible, given in a form relevant to experimental application.The technique is detailed in the setting of trapped-ion experiments with two-photon Raman interaction, where the desired open dynamics is obtained from stochastically shaking the trapping potential, or driving the system with a laser of stochastic amplitude. In this context, we find solutions for the control parameters---namely laser amplitude, phase, and dephasing strength---that allow creating a squeezed thermal state at controlled temperature in arbitrary time.

•Aug 7, 2020•3 citations

Superadiabatic thermalization of a quantum oscillator by engineered dephasing

L. Dupays, I. L. Egusquiza, A. del Campo +1 more

This paper proposes the fast control of open quantum systems in Gaussian states through experimentally implementable protocols. The authors develop shortcuts to adiabaticity for the fast thermalization of a quantum oscillator using stochastic parametric driving.

arXiv:1910.12088•Physical Review Research•Aug 3, 2020•30 citations

Continuous-time quantum harmonic oscillator state engineering

E. García Herrera, F. Torres-Leal, B. M. Rodríguez-Lara

Abstract The center of mass motion of trapped ions and neutral atoms is suitable for approximation by a time-dependent driven quantum harmonic oscillator whose frequency and driving strength may be controlled with high precision. We show the time evolution for these systems with continuous differentiable time-dependent parameters in terms of the three basic operations provided by its underlying symmetry, rotation, displacement, and squeezing, using a Lie algebraic approach. Our factorization of the dynamics allows for the intuitive construction of protocols for state engineering, for example, creating and removing displacement and squeezing, as well as their combinations, optimizing squeezing, or more complex protocols that work for slow and fast rates of change in the oscillator parameters.

arXiv:2304.08351•New Journal of Physics•Dec 1, 2023•5 citations

Driven quantum harmonic oscillators: A working medium for thermal machines

Heather Leitch, Nicolò Piccione, Bruno Bellomo +1 more

The study of quantum thermodynamics is key to the development of quantum thermal machines. In contrast to most of the previous proposals based on discrete strokes, here we consider a working substance that is permanently coupled to two or more baths at different temperatures and continuously driven. To this end, we investigate parametrically driven quantum harmonic oscillators coupled to heat baths via a collision model. Using a thermodynamically consistent local master equation, we derive the heat flows and power of the working device, which can operate as an engine, refrigerator, or accelerator, and analyze the instantaneous and average efficiencies and coefficients of performance. Studying the regimes of both slow and fast driving of the system, we find that an increased driving frequency can lead to a change of functioning to a dissipator. Finally, we investigate the effect of squeezing one of the thermal baths: it leads to an apparent higher efficiency compared to the corresponding Carnot value of an equilibrium bath with the same temperature and to sustained entanglement between the working substance oscillators in the limit cycle.

arXiv:2108.11341•AVS Quantum Science•Feb 3, 2022•20 citations

Optimal protocol to increase the lifetime of a harmonic oscillator via a squeezing reservoir

Yong-Qi Liu, Y.-M. Du, Xiaoguang Wang

Reservoir engineering makes it possible to adjust the dissipation of quantum systems by driving the reservoir. This inspires investigations on how to slow a system's damping via squeezing reservoirs. In this paper we characterize damping by the quantum reliability of quantum states. We analyze the reliability loss of the harmonic oscillators in a squeezed thermal reservoir, where the quantum states under consideration have garnered significant interest in recent experiments, such as the coherent state, the squeezed coherent state, and the cat state. We explore the optimal protocol to extend the lifetime of these quantum states by adjusting the squeezed parameters of the squeezed thermal reservoir in both the high-damping and low-damping regimes. In the low-damping regime, our findings suggest that the unique optimal protocol follows the phase-matching condition and is insensitive to the reservoir's temperature. We also evaluate the optimal condition for the large damping regime. Furthermore, we show that when the state parameters satisfy a specific condition, there exists an interval for the damping rate, within which a bifurcation of the optimal protocol occurs.

Physical Review A•Jul 25, 2025•1 citation

Effective temperature pulses in open quantum systems

Pedro Portugal, Fredrik Brange, Christian Flindt

Controlling the temperature of nanoscale quantum systems is becoming increasingly important in the efforts to develop thermal devices such as quantum heat valves, heat engines, and refrigerators and to explore fundamental concepts in quantum thermodynamics. In practice, however, it is challenging to generate arbitrary time-dependent temperatures, similarly to what has been achieved for electronic voltage pulses. To overcome this problem, we here propose a fully quantum mechanical scheme to control the time-dependent environment temperature of an open quantum system. To this end, we consider a collection of quantum harmonic oscillators that mediate the interactions between the quantum system and a thermal reservoir, and we show how an effective time-dependent temperature can be realized by modulating the oscillator frequencies in time. By doing so, we can apply effective temperature pulses to the quantum system, and it can be cooled below the temperature of the environment. Surprisingly, the scheme can be realized using only a few oscillators, and our proposal thereby paves the way for controlling the temperature of open quantum systems.

arXiv:2204.05730•Physical Review Research•Nov 17, 2022•15 citations
Squeezed state in harmonic systems can be generated through a variety of techniques, including varying the oscillator frequency or using nonlinear two-photon Raman interaction. We focus on these two techniques to drive an initial thermal state into a final squeezed thermal state with controlled squeezing parameters – amplitude and phase – in arbitrary time. The protocols are designed through reverse engineering for both unitary and open dynamics. Control of the dissipation is achieved using stochastic processes, readily implementable via, e.g., continuous quantum measurements. Importantly, this allows controlling the state entropy and can be used for fast thermalization. The developed protocols are thus suited to generate squeezed thermal states at controlled temperature in arbitrary time.
Control protocols known as shortcuts to adiabaticity allow to drive a quantum system from an initial to a final state arbitrarily fast. These techniques have recently been proposed for open quantum systems, thus extending their application to allow for fast thermalization. Here, we engineer dynamical schemes for the fast preparation of squeezed thermal states at controlled temperature. We derive the equations of motion of squeezed thermal states in harmonic oscillators under unitary and open dynamics, allowing for temperature and entropy variations between the initial and final states. The counter-diabatic Hamiltonians and associated dissipators are provided, and whenever possible, given in a form relevant to experimental application.The technique is detailed in the setting of trapped-ion experiments with two-photon Raman interaction, where the desired open dynamics is obtained from stochastically shaking the trapping potential, or driving the system with a laser of stochastic amplitude. In this context, we find solutions for the control parameters---namely laser amplitude, phase, and dephasing strength---that allow creating a squeezed thermal state at controlled temperature in arbitrary time.
Abstract The center of mass motion of trapped ions and neutral atoms is suitable for approximation by a time-dependent driven quantum harmonic oscillator whose frequency and driving strength may be controlled with high precision. We show the time evolution for these systems with continuous differentiable time-dependent parameters in terms of the three basic operations provided by its underlying symmetry, rotation, displacement, and squeezing, using a Lie algebraic approach. Our factorization of the dynamics allows for the intuitive construction of protocols for state engineering, for example, creating and removing displacement and squeezing, as well as their combinations, optimizing squeezing, or more complex protocols that work for slow and fast rates of change in the oscillator parameters.
The study of quantum thermodynamics is key to the development of quantum thermal machines. In contrast to most of the previous proposals based on discrete strokes, here we consider a working substance that is permanently coupled to two or more baths at different temperatures and continuously driven. To this end, we investigate parametrically driven quantum harmonic oscillators coupled to heat baths via a collision model. Using a thermodynamically consistent local master equation, we derive the heat flows and power of the working device, which can operate as an engine, refrigerator, or accelerator, and analyze the instantaneous and average efficiencies and coefficients of performance. Studying the regimes of both slow and fast driving of the system, we find that an increased driving frequency can lead to a change of functioning to a dissipator. Finally, we investigate the effect of squeezing one of the thermal baths: it leads to an apparent higher efficiency compared to the corresponding Carnot value of an equilibrium bath with the same temperature and to sustained entanglement between the working substance oscillators in the limit cycle.
Reservoir engineering makes it possible to adjust the dissipation of quantum systems by driving the reservoir. This inspires investigations on how to slow a system's damping via squeezing reservoirs. In this paper we characterize damping by the quantum reliability of quantum states. We analyze the reliability loss of the harmonic oscillators in a squeezed thermal reservoir, where the quantum states under consideration have garnered significant interest in recent experiments, such as the coherent state, the squeezed coherent state, and the cat state. We explore the optimal protocol to extend the lifetime of these quantum states by adjusting the squeezed parameters of the squeezed thermal reservoir in both the high-damping and low-damping regimes. In the low-damping regime, our findings suggest that the unique optimal protocol follows the phase-matching condition and is insensitive to the reservoir's temperature. We also evaluate the optimal condition for the large damping regime. Furthermore, we show that when the state parameters satisfy a specific condition, there exists an interval for the damping rate, within which a bifurcation of the optimal protocol occurs.
Controlling the temperature of nanoscale quantum systems is becoming increasingly important in the efforts to develop thermal devices such as quantum heat valves, heat engines, and refrigerators and to explore fundamental concepts in quantum thermodynamics. In practice, however, it is challenging to generate arbitrary time-dependent temperatures, similarly to what has been achieved for electronic voltage pulses. To overcome this problem, we here propose a fully quantum mechanical scheme to control the time-dependent environment temperature of an open quantum system. To this end, we consider a collection of quantum harmonic oscillators that mediate the interactions between the quantum system and a thermal reservoir, and we show how an effective time-dependent temperature can be realized by modulating the oscillator frequencies in time. By doing so, we can apply effective temperature pulses to the quantum system, and it can be cooled below the temperature of the environment. Surprisingly, the scheme can be realized using only a few oscillators, and our proposal thereby paves the way for controlling the temperature of open quantum systems.