- 标题
- 摘要
- 关键词
- 实验方案
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Optomechanical damping basis
摘要： We present a closed-form analytical solution to the eigenvalue problem of the Liouville operator generating the dissipative dynamics of the standard optomechanical system. The corresponding Lindblad master equation describes the dynamics of a single-mode field inside an optical cavity coupled by radiation pressure to its moving mirror. The optical field and the mirror are in contact with separate environments, which are assumed at zero and finite temperature, respectively. The optomechanical damping basis refers to the exact set of eigenvectors of the generator that, together with the exact eigenvalues, are explicitly derived. Both the weak- and the strong-coupling regime, which includes combined decay mechanisms, are solved in this work.
关键词： Open quantum systems,Decoherence,Optomechanics
更新于2025-09-23 15:22:29
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Theoretical study on optical response in nanostructures in the Born–Markov regime: The role of spontaneous emission and dephasing
摘要： We theoretically study the linear and nonlinear optical susceptibility in a nanostructure that interacts with a classical monochromatic optical field, by means of the solution of a Born-Markov master equation in the Lindblad form, considering as environment for the system the quantum vacuum of the continuum of modes of the external electromagnetic field. The processes of spontaneous emission and dephasing between two levels of the nanostructured quantum system are studied formally, within the framework of the quantum theory of open systems. It was found that the phenomenological master equation corresponds to a Born-Markov master equation in the Lindblad form that considers only the dissipative terms of spontaneous emission and dephasing, provided that the transverse coherence time is smaller than spontaneous emission time . Finally, comparative results are presented between the proposed methodology and the conventional method for: optical rectification, optical absorption, generation of second harmonic and generation of third harmonic in a cylindrical quantum dot (CQD) of with a hydrogen-like impurity inside it and under the action of a uniform magnetic field.
关键词： Lindblad,quantum dot,Optical susceptibility,Born-Markov,open quantum systems
更新于2025-09-23 15:21:21
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$${\mathscr{P}}{\mathscr{T}}$$PT-symmetric interference transistor
摘要： We present a model of the molecular transistor, operation of which is based on the interplay between two physical mechanisms, peculiar to open quantum systems that act in concert: PT-symmetry breaking corresponding to coalescence of resonances at the exceptional point of the molecule, connected to the leads, and Fano-Feshbach antiresonance. This switching mechanism can be realised in particular in a special class of molecules with degenerate energy levels, e.g. diradicals, which possess mirror symmetry. At zero gate voltage infinitesimally small interaction of the molecule with the leads breaks the PT-symmetry of the system that, however, can be restored by application of the gate voltage preserving the mirror symmetry. PT-symmetry broken state at zero gate voltage with minimal transmission corresponds to the “off” state while the PT-symmetric state at non-zero gate voltage with maximum transmission – to the “on” state. At zero gate voltage energy of the antiresonance coincides with exceptional point. We construct a model of an all-electrical molecular switch based on such transistors acting as a conventional CMOS inverter and show that essentially lower power consumption and switching energy can be achieved, compared to the CMOS analogues.
关键词： diradicals,molecular transistor,CMOS inverter,quantum systems,PT-symmetric interference,Fano-Feshbach antiresonance
更新于2025-09-23 15:21:21
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Avoided Crossing and sub-Fourier-sensitivity in Driven Quantum Systems
摘要： The response of a linear system to an external perturbation is governed by the Fourier limit, with the inverse of the interaction time constituting a lower limit for the system bandwidth. This does not hold for nonlinear systems, which can thus exhibit sub-Fourier-behavior. The present Letter identifies a mechanism for sub-Fourier-sensitivity in driven quantum systems, which relies on avoided crossing between Floquet states. Features up to three orders of magnitude finer than the Fourier limit are presented.
关键词： driven quantum systems,Floquet states,avoided crossing,sub-Fourier-sensitivity
更新于2025-09-23 15:21:21
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[Texts and Readings in Physical Sciences] Open Quantum Systems Volume 20 (Dynamics of Nonclassical Evolution) || Open Quantum System at Interface with Quantum Information
摘要： This chapter is devoted to the interface between open system ideas and the burgeoning field of quantum information. Quantum information is, as the name suggests, the broad name given to information tasks that make use of the laws of quantum mechanics. It encompasses within its purview, communication, computation and foundational information theoretical tasks. Information theoretic ideas pervade the whole of physics and make inroads beyond it. As it involves encoding, transmission and decoding of information as bits or qubits, all of which are very sensitive to their ambient environment, they provide a fruitful ground for the application of open system ideas. In fact, this chapter and the next one bear testimony to this.
关键词： quantum information,open quantum systems,quantum computation,quantum error correction,quantum communication
更新于2025-09-23 15:21:01
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Precision Limits in Quantum Metrology with Open Quantum Systems
摘要： The laws of quantum mechanics allow to perform measurements whose precision supersedes results predicted by classical parameter estimation theory. That is, the precision bound imposed by the central limit theorem in the estimation of a broad class of parameters, like atomic frequencies in spectroscopy or external magnetic field in magnetometry, can be overcome when using quantum probes. Environmental noise, however, generally alters the ultimate precision that can be achieved in the estimation of an unknown parameter. This tutorial reviews recent theoretical work aimed at obtaining general precision bounds in the presence of an environment. We adopt a complementary approach, where we first analyze the problem within the general framework of describing the quantum systems in terms of quantum dynamical maps and then relate this abstract formalism to a microscopic description of the system’s dissipative time evolution. We will show that although some forms of noise do render quantum systems standard quantum limited, precision beyond classical bounds is still possible in the presence of different forms of local environmental fluctuations.
关键词： precision limits,open quantum systems,frequency estimation
更新于2025-09-23 15:21:01
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Theory of valley-resolved spectroscopy of a Si triple quantum dot coupled to a microwave resonator
摘要： We theoretically study a silicon triple quantum dot (TQD) system coupled to a superconducting microwave resonator. The response signal of an injected probe signal can be used to extract information about the level structure by measuring the transmission and phase shift of the output field. This information can further be used to gain knowledge about the valley splittings and valley phases in the individual dots. Since relevant valley states are typically split by several μeV, a finite temperature or an applied external bias voltage is required to populate energetically excited states. The theoretical methods in this paper include a capacitor model to fit experimental charging energies, an extended Hubbard model to describe the tunneling dynamics, a rate equation model to find the occupation probabilities, and an input–output model to determine the response signal of the resonator.
关键词： quantum dots,hybrid quantum systems,spin qubits,valley,silicon,cavity QED
更新于2025-09-23 15:19:57
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Density matrix superoperator for periodic quantum systems and its application to quantum cascade laser structures
摘要： In this work we present a generalization of the Liouvillian superoperator for periodic quantum systems that can be formulated through partitioned Hamiltonians. We formulate a compact algebraic form of the superoperator that allows efficient numerical implementation along with the possibility of further generalization and the inclusion of the system’s boundary effects (i.e. device contacts). We apply this formalism to Quantum Cascade Laser structure where we compare the second nearest and the nearest on approximation, and present the laser dynamics that is independent from the number of states considered.
关键词： Liouvillian superoperator,periodic quantum systems,density matrix,Khatri-Rao product,Quantum Cascade Laser
更新于2025-09-12 10:27:22
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Hybrid spin-superconducting quantum circuit mediated by deterministically prepared entangled photonic states
摘要： In hybrid quantum systems, a controllable coupling can be obtained by mediating the interactions with dynamically introduced photons. We propose a hybrid quantum architecture consisting of two nitrogen vacancy center ensembles coupled to a tunable flux qubit, which is contained on the transmission line of a multimode nonlinear superconducting coplanar waveguide resonator with an appended Josephson mixing device. We discuss the use of entangled propagating microwaves photons, which through our nonlinear wave-mixing procedure are made into macroscopically distinct quantum states. We use these states to steer the system and show that, with further amplification, we can create a similar photonic state, which has a more distinct reduction of its uncertainty. Furthermore, we show that all of this leads to a lengthened coherence time, a reasonable fidelity that decays to 0.94 and then later increases upward to stabilize at 0.6, as well as a strengthened entanglement.
关键词： squeezed Schr?dinger cat state,entangled microwaves photons,Schr?dinger cat state,flux qubit,nitrogen vacancy center ensembles,superconducting coplanar waveguide resonator,hybrid quantum systems
更新于2025-09-12 10:27:22
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Applications of the Holographic Duality to Strongly Coupled Quantum Systems
摘要： The holographic duality represents a major advance in our understanding of string theory and quantum gravity and also provides a powerful toolkit for studying strongly coupled quantum field theories. Thanks to this duality, challenging questions about dynamics in quantum phases of matter in strong coupling regime can be mapped to processes in theories of gravity which are tractable. It was proven to be very useful in describing unconventional physics in many fields, such as gauge theory, condensed matter, information theory, and systems described by hydrodynamics.
关键词： quantum field theories,holographic duality,string theory,quantum gravity,strongly coupled quantum systems
更新于2025-09-11 14:15:04