arXiv subjects

Jun Jing

Publications and source records attributed to Jun Jing.

At least 55 records · Page 3Linked to original sources

arXiv2022

Accelerated adiabatic passage in cavity magnomechanics

Cavity magnomechanics provides a readily-controllable hybrid system, that consisted of cavity mode, magnon mode, and phonon mode, for quantum state manipulation. To implement a fast-and-robust state transfer between the hybrid photon-magnon mode and the phonon mode, we propose two accelerated adiabatic-passage protocols individually based on the counterdiabatic Hamiltonian for transitionless quantum driving and the Levis-Riesenfeld invariant for inverse engineering. Both the counterdiabatic Hamiltonian and the Levis-Riesenfeld invariant generally apply to the continuous-variable systems with arbitrary target states. It is interesting to find that our counterdiabatic Hamiltonian can be constructed in terms of the creation and annihilation operators rather than the system-eigenstates and their time-derivatives. Our protocol can be optimized with respect to the stability against the systematic errors of coupling strength and frequency detuning. It contributes to a quantum memory for photonic and magnonic quantum information. We also discuss the effects from dissipation and the counter-rotating interactions.

quant-ph↗

arXiv2021

External-level assisted cooling by measurement

A quantum resonator in a thermal-equilibrium state with a high temperature has a large average population and is featured with significant occupation over Fock states with a high excitation number. The resonator could be cooled down via continuous measurements on the ground state of a coupled two-level system (qubit). We find, however, that the measurement-induced cooling might become inefficient in the high-temperature regime. Beyond the conventional strategy, we introduce strong driving between the excited state of the qubit and an external level. It can remarkably broaden the cooling range in regard to the non-vanishing populated Fock states of the resonator. Without any precooling procedure, our strategy allows a significant reduction of the populations over Fock states with a high excitation number, giving rise to nondeterministic ground-state cooling after a sequence of measurements. The driving-induced fast transition constrains the resonator and the ancillary qubit at their ground state upon measurement and then simulates the quantum Zeno effect. Our protocol is applied to cool down a high-temperature magnetic resonator. Additionally, it is generalized to a hybrid cooling protocol by interpolating the methods with and without strong driving, which can accelerate the cooling process and increase the overlap between the final state of the resonator and its ground state.

quant-ph↗

arXiv2021

One-component quantum mechanics and dynamical leakage-free paths

We derive an exact one-component equation of motion for the probability amplitude of a target time-dependent state, and use the equation to reformulate quantum dynamics and control for both closed and open systems. Using the one-component equation, we show that an unexpected time-dependent leakage-free path can be induced and we capture the essential quantity in determining the effect of decoherence suppression. Our control protocol based on the nonperturbative leakage elimination operator provides a unified perspective connecting some subtle, popular and important concepts of quantum control, such as dynamical decoupling, quantum Zeno effect, and adiabatic passage. The resultant one-component equation will promise significant advantages in both quantum mechanics and control.

quant-ph↗

arXiv2021

Generation of Bell and GHZ states from a hybrid qubit-photon-magnon system

We propose a level-resolved protocol in a hybrid architecture for connecting a superconducting qubit and a magnon mode contained within a microwave cavity (resonator) to generate the local and global entangled states, enabling a wide range of applications in quantum communication, quantum metrology, and quantum information processing. Exploiting the high-degree of controllability in such a hybrid qubit-photon-magnon system, we derive effective Hamiltonians at the second- or the third-order resonant points by virtue of the strong counter-rotating interactions between the resonator and the qubit and between the resonator and the magnon. Consequently, we can efficiently generate the Bell states of the photon-magnon and the qubit-magnon subsystems and the Greenberger-Horne-Zeilinger state of the whole hybrid system. We also check the robustness of our protocol against the environmental noise by the Lindblad master equation. Our work makes this hybrid platform of high-degree of controllability a high-fidelity candidate for the realization of the maximally-entangled multiple states.

quant-ph↗

arXiv2021

Magnon-mediated quantum battery under systematic errors

Quantum battery is one of the most prominent micro-devices in the rapid-developing quantum thermodynamics. We propose a quantum charging protocol in which both battery and charger are consisted of a many-spin system. The battery and charger are connected via the Kittle mode of the magnon system, that serves as a charging wire and then enables a long-range charging protocol. Counter-intuitively, we find that the spin-spin couplings insider both battery and charger can be used to promote the charging performance in comparison to the noninteracting condition. And a remarkable promotion is realized at a "sweet" spot in terms of the average coupling strength. Moreover, we apply the quantum-state-diffusion equation to test the robustness of our magnon-mediated charging protocol to the systematic errors about the magnon frequency.

quant-ph↗

arXiv2021

High-capacity and high-power collective charging with spin chargers

Quantum battery works as a micro- or nano-device to store and redistribute energy at the quantum level. Here we propose a spin-charger protocol, in which the battery cells are charged by a finite number of spins through a general Heisenberg XY interaction. Under the isotropic interaction, the spin-charger protocol is endowed with a higher capacity in terms of the maximum stored energy than the conventional protocols, where the battery is charged by a continuous-variable system, e.g., a cavity mode. By tuning the charger size, a trade-off between the maximum stored energy and the average charging power is found in comparison to the cavity-charger protocol in the Tavis-Cummings model. Quantum advantage of our protocol is manifested by the scaling behavior of the optimal average power with respect to the battery size, in comparing the collective charging scheme to its parallel counterpart. We also discuss the detrimental effect on the charging performance from the anisotropic interaction between the battery and the charger, the non-ideal initial states for both of them, and the crosstalk among the charger spins. A strong charger-charger interaction can be used to decouple the battery and the charger. Our findings about the advantages of the spin-charger protocol over the conventional cavity-charger protocols, including the high capacity of energy storage and the superior power-law in the collective charging, provide an insight to exploit an efficient quantum battery based on the spin-spin-environment model.

quant-ph↗

arXiv2021

Fast and stable charging via a shortcut to adiabaticity

Quantum battery is an emerging subject in the field of quantum thermodynamics, which is applied to charge, store and dispatch energy in quantum systems. In this work, we propose a fast and stable charging protocol based on the adiabatic evolution for the dark state of a three-level quantum battery. It combines the conventional stimulated Raman adiabatic passage (STIRAP) and the quantum transitionless driving technique. The charging process can be accelerated up to nearly one order in magnitude even under constraint of the strength of counter-diabatic driving. To perform the charging protocol in the Rydberg atomic system as a typical platform for STIRAP, the prerequisite driving pulses are modified to avoid the constraint of the forbidden transition. Moreover, our protocol is found to be more robust against the environmental dissipation and dephasing than the conventional STIRAP.

quant-ph↗

arXiv2021

Magnon-assisted photon-phonon conversion in the presence of the structured environments

Quantum conversion or interface is one of the most prominent protocols in quantum information processing and quantum state engineering. We propose a photon-phonon conversion protocol in a hybrid magnomechanical system comprising a microwave optical mode, a driven magnon mode and a mechanical-vibrating mode. The microwave photons in the optical cavity are coupled to the magnons by the magnetic-dipole interaction, and the latter are coupled to the mechanical phonons by the magnetostrictive interaction. With strong photon-magnon interaction and strong driving on magnon, an effective Hamiltonian is constructed to describe the conversion between photons and phonons nearby their resonant point. The cavity-magnon system can then play the role of a quantum memory. Moreover, the faithfulness of the photon-phonon conversion is estimated in terms of fidelities for state evolution and state-independent transfer. The former is discussed in the Lindblad master equation taking account the leakages of photon, phonon and magnon into consideration. The latter is derived by the Heisenberg-Langevin equation considering the non-Markovian noise from the structured environments for both optical and mechanical modes. The state-evolution fidelity is found to be robust to the weak leakage. The transfer fidelity can be maintained by the Ohmic and sub-Ohmic environments of the photons and is insensitive to the $1/f$ noise of the phonons. Our work thus provides an interesting application for the magnon system as a photon-phonon converter in the microwave regime.

quant-ph↗

arXiv2021

Possible implications for particle physics by quantum measurement

In sharp contrast to its classical counterpart, quantum measurement plays a fundamental role in quantum mechanics and blurs the essential distinction between the measurement apparatus and the objects under investigation. An appealing phenomenon in quantum measurements, termed as quantum Zeno effect, can be observed in particular subspaces selected by measurement Hamiltonian. Here we apply the top-down Zeno mechanism to the particle physics. We indeed develop an alternative insight into the properties of fundamental particles, but not intend to challenge the Standard Model (SM). In a unified and simple manner, our effective model allows to merge the origin of neutrino's small mass and oscillations, the hierarchy pattern for masses of electric charged fermions, the color confinement, and the discretization of quantum numbers, using a perturbative theory for the dynamical quantum Zeno effect. Under various conditions for vanishing transition amplitudes among particle eigenstates in the effective model, it is remarkable to probe results that are somewhat reminiscent of SM, including: (i) neutrino oscillations with big-angle mixing and small masses emerge from the energy-momentum conservation, (ii) electrically-charged fermions hold masses in a hierarchy pattern due to the electric-charge conservation, (iii) color confinement and the associated asymptotic freedom can be deduced from the color-charge conservation. We make several anticipations about the basic properties for fundamental particles: (i) the total mass of neutrinos and the existence of a nearly massless neutrino (of any generation), (ii) the discretization in quantum numbers for the new-discovered electrically-charged fermions, (iii) the confinement and the associated asymptotic freedom for any particle containing more than two conserved charges.

hep-ph↗

arXiv2021

A multifunctional quantum thermal device: with and without inner coupling

A three-level system attached to three thermal baths is manipulated to be a microscopic thermal device integrating a valve, a refrigerator, an amplifier, and a thermometer in the quantum regime, via tuning the inner coupling strength of the system and the temperatures of the external baths. We discuss the role of the inner coupling as well as the steady-state quantum coherence in these thermal functions using the Redfield master equation under a partial secular approximation. A high-sensitive thermometer for the low-temperature terminal can be established without the assistance from the inner coupling of the system. Our study of this multifunctional thermal device provides a deeper insight to the underlying quantum thermodynamics associated with the quantum coherence.

quant-ph↗

arXiv2020

Coherent noise cancellation in optomechanical system with double optical modes

The coherent quantum noise cancellation (CQNC) strategy has been performed in the single-mode optomechanical systems to promote an ultra-sensitive metrology protocol to break the standard quantum limit. The key idea of CQNC is that the backaction noises arising from radiation pressure and driving can be offset by coupling the optical mode to a near-resonant ancillary mode. In this work, a continuous weak-force sensing under CQNC is developed in a double-mode optomechanical system consisted of two optical modes with distinct frequencies and a mechanical mode. In particular, under the asymmetrical treatment by driving the higher-frequency optical mode, probing the lower-frequency one, and coupling the probe mode to the ancillary mode, our configuration can be used to resemble the conventional CQNC sensing. It is more important to find that the current CQNC strategy simultaneously stabilizes the double-mode system with respect to both the constrained driving power (the Routh-Hurwitz criterion) and the effective positive mechanical damping (the stable optical-spring condition). Moreover, through exploiting the coupling between the probe mode and the ancillary mode under this nontrivial extension of the CQNC strategy (from the single-mode version to the double-mode one), the rotating-wave term and the counter-rotating term are found to be responsible to the system stability and the noise cancellation, respectively. In realistic situations, our scheme can be practiced in a tripartite optomechanical setup with a membrane in the middle and a twisted-cavity-based weak-torque detector.

quant-ph↗

arXiv2020

Quantum Zeno effects across a parity-time symmetry breaking transition in atomic momentum space

We experimentally study quantum Zeno effects in a parity-time (PT) symmetric cold atom gas periodically coupled to a reservoir. Based on the state-of-the-art control of inter-site couplings of atoms in a momentum lattice, we implement a synthetic two-level system with passive PT symmetry over two lattice sites, where an effective dissipation is introduced through repeated couplings to the rest of the lattice. Quantum Zeno (anti-Zeno) effects manifest in our experiment as the overall dissipation of the two-level system becoming suppressed (enhanced) with increasing coupling intensity or frequency. We demonstrate that quantum Zeno regimes exist in the broken PT symmetry phase, and are bounded by exceptional points separating the PT symmetric and PT broken phases, as well as by a discrete set of critical coupling frequencies. Our experiment establishes the connection between PT-symmetry-breaking transitions and quantum Zeno effects, and is extendable to higher dimensions or to interacting regimes, thanks to the flexible control with atoms in a momentum lattice.

cond-mat.quant-gas↗

arXiv2019

Generating NOON states in circuit QED using multi-photon resonance in the presence of counter-rotating interactions

The NOON states are valuable quantum resources, which have a wide range of applications in quantum communication, quantum metrology, and quantum information processing. Here we propose a fast, concise and reliable protocol for deterministically generating the NOON states of two resonators coupled to a single $\triangle$-type superconducting qutrit. In particular, we derive the effective Hamiltonians at the multi-photon resonances by virtue of the strong counter-rotating interaction between the resonator modes and the qutrit. Based on these crucial effective Hamiltonians, our protocol simplifies the previous ones using the single-photon resonance and consequently reduces the number of operations for state preparation. To test the robustness of this protocol, we analyze the effects from both the decoherence including dissipation and dephasing and the crosstalk of resonator modes on the state fidelity through a Lindblad master equation in the eigenstates of the full Hamiltonian.

quant-ph↗

arXiv2019

Berry-phase-based quantum gates assisted by transitionless quantum driving

We propose a novel proposal for geometric quantum gates using three- or two-level systems, in which a controllable variable, the detuning between the driving frequency and the atomic energy spacing, is introduced to realize geometric transformations. In particular, we can have two instantaneous eigenstates with opposite eigenvalues constituting a closed loop in the parameter space. The accumulated dynamical phase is then exactly cancelled when the loop is completed, which is beyond the traditional parallel-transport restriction. We apply the transitionless quantum driving, which renders revisions in both amplitudes and phases of the driving fields, to enhance the speed and the fidelity of geometric transformation in both universal single-qubit gates and nontrivial double-qubit gates. Gate fidelity under decoherence is also estimated.

quant-ph↗

arXiv2019

Measurement-induced cooling of a qubit in structured environments

In this work, we study the thermodynamics of a two-level system (qubit) embedded in a finite-temperature structured-bath under periodical measurements. The system under measurements will reach a quasi-steady state, whose effective temperature can be maintained lower than that of the surrounding environment. To study the influence of the environmental oscillators from different regimes of frequency on the qubit, the spectrum of the bath consisting of a large number of bosonic harmonic oscillators can be approximately divided into three parts according to their effects of cooling or heating. Due to the spectral analysis over the structured-bath based on the non-Markovian master equation beyond the rotating-wave approximation, we propose a sufficient cooling condition for the bath in the context of quantum non-selective measurement. It is consisted of two items: (i) the logarithmic derivative of the spectrum around the system transition frequency is large enough, at least larger than one half of the inverse temperature of the bath; (ii) the spectrum should have a sharp high-frequency cutoff that is not far-detuning from the system transition frequency. From this condition, we find that two popular types of spectra, i.e., the modified Lorentzian models and the super-Ohmic models, are available environments for cooling the open quantum system.

quant-ph↗

arXiv2019

Quantumness protection for open systems in a double-layer environment

We study the dynamics of the two-level atomic systems (qubits) under a double-layer environment that is consisted of a network of single-mode cavities coupled to a common reservoir. A general exact master equation for the dynamics can be obtained by the quantum-state-diffusion (QSD) equation. The quantumness of the atoms including coherence and entanglement is investigated within various configurations of the external environment. It is shown that the preservation and generation of the quantumness can be controlled by regulating the parameters of the cavity network. Moreover the underlying physics of the results can be profoundly revealed by an effective model via a unitary transformation. Our work provides an interesting proposal in protecting the quantumness of open systems in the framework of a double-layer environment containing bosonic modes.

quant-ph↗

arXiv2019

Exact coherence dynamics mediated by a single cavity mode in the presence of leakage

We present a quantum-state-diffusion equation to characterize the dynamics of a generic atomic system coupled to a leaky cavity mode. As quantum resources, the population, the coherence and even the entanglement of the system would gradually leak out of the cavity. The effect from the leakage of the cavity-mode to the uncontrollable degree of freedom, e.g., environment, is however not always negative to particular targets. A well-established scenario is that a photon counter attached to the cavity would absorb and then record the leaking photon. As a medium between the system and the photon counter, a strong coupling between system and cavity is necessary to enhance the measurement efficiency. While we find it also reduce the reading efficiency of the photon counter at the same time as fewer photons leak out of the cavity. We investigate the competition between these two mechanisms in the framework of non-Markovian open-quantum-system dynamics, where the photon counter serves as a general bosonic environment. Our results provide an optimized parameter space for system entanglement preservation and generation.

quant-ph↗

arXiv2018

Microwave-controlled optical double optomechanically induced transparency in a hybrid piezo-optomechanical cavity system

We propose a scheme that is able to generate the microwave controlled optical double optome-chanical induced transparency (OMIT) in a hybrid piezo-optomechanical cavity system, which a piezoelectric optomechanical crystal AlN-nanobeam resonator is placed in a superconducting microwave cavity, and the AlN-nanobeam resonator can be simultaneously driven by both the optical field via the radiation pressure and the microwave field via the piezoelectric interaction. We show that in the presence of a strong pumped optical field applied to the optomechanical crystal cavity through the optical waveguide and an intensely stimulated microwave field applied to the superconducting microwave cavity, a double-OMIT window can be observed in the weak output probe field. The mechanism is that a N-type four-level system can be formed by the system, when two driving fields and a probe field are applied to the corresponding levels, under the effect of quantum interference between different energy level pathways, the third-order nonlinear absorption is enhanced by the constructive quantum interference while the linear absorption is inhibited by the destruc- tive quantum interference, as a result, the double-OMIT window is generated. Our scheme can be applied to realize high-speed optical switches, high-resolution spectroscopy, coherent population trapping or quantum information processing in the solid state quantum systems.

quant-ph↗