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We experimentally demonstrate a mode-selective quantum frequency converter over a compound spatio-temporal Hilbert space. We show that our method can achieve high-extinction for high-dimensional quantum state tomography by selectively…

Quantum Physics · Physics 2021-08-11 Santosh Kumar , He Zhang , Prajnesh Kumar , Malvika Garikapati , Yong Meng Sua , Yu-Ping Huang

Voltage fluctuations are common disturbances in power grids. Initially, it is necessary to selectively identify individual sources of voltage fluctuations to take actions to minimize the effects of voltage fluctuations. Selective…

Signal Processing · Electrical Eng. & Systems 2023-06-16 Piotr Kuwałek

Light-pulse atom interferometers are powerful quantum sensors, however, their accuracy for example in tests of the weak equivalence principle is limited by various spurious influences like magnetic stray fields or blackbody radiation.…

Quantum Physics · Physics 2020-05-12 Christian Ufrecht , Enno Giese

Based on the path integral representation of the partition function of a many body system with separable two body interaction we propose a systematic extension of the perturbed static path approximation (PSPA) to lower temperatures.…

Statistical Mechanics · Physics 2009-11-07 Christian Rummel , Joachim Ankerhold

We derive Hamiltonian flow equations giving the evolution of the Lipkin Hamiltonian to a diagonal form using continuous unitary transformations. To close the system of flow equations, we present two different schemes. First we linearize an…

Nuclear Theory · Physics 2009-10-31 H. J. Pirner , B. Friman

Hamilton's equations with noise and friction possess a hidden supersymmetry, valid for time-independent as well as periodically time-dependent systems. It is used to derive topological properties of critical points and periodic trajectories…

Statistical Mechanics · Physics 2007-05-23 Julien Tailleur , Sorin Tanase-Nicola , Jorge Kurchan

The averaging method is a classical powerful tool in perturbation theory of dynamical systems. There are two major obstacles to applying the averaging method, resonances and separatrices. In this paper we obtain realistic asymptotic…

Dynamical Systems · Mathematics 2022-02-14 Anatoly Neishtadt , Alexey Okunev

The observation of genuine quantum effects in systems governed by non-Hermitian Hamiltonians has been an outstanding challenge in the field. Here we simulate the evolution under such Hamiltonians in the quantum regime on a superconducting…

Quantum Physics · Physics 2021-11-24 Shruti Dogra , Artem A. Melnikov , Gheorghe Sorin Paraoanu

We describe some general results that constrain the dynamical fluctuations that can occur in non-equilibrium steady states, with a focus on molecular dynamics. That is, we consider Hamiltonian systems, coupled to external heat baths, and…

Statistical Mechanics · Physics 2017-11-22 Robert L. Jack , Marcus Kaiser , Johannes Zimmer

When measuring the value of a function to be minimized is not only expensive but also with noise, the popular simultaneous perturbation stochastic approximation (SPSA) algorithm requires only two function values in each iteration. In this…

Optimization and Control · Mathematics 2022-03-08 Shiru Li , Yong Xia , Zi Xu

We develop a quantum reductive perturbation method (RPM), a generalization of classical RPM widely used in nonlinear wave theory, to derive a simplified model (i.e. quantum nonlinear Schrodinger equation) from fully quantum…

Quantum Physics · Physics 2024-06-13 Ou Yao , Huang Guoxiang

Quantum optimal control represents a powerful technique to enhance the performance of quantum experiments by engineering the controllable parameters of the Hamiltonian. However, the computational overhead for the necessary optimization of…

We simulate the excited states of the Lipkin model using the recently proposed Quantum Equation of Motion (qEOM) method. The qEOM generalizes the EOM on classical computers and gives access to collective excitations based on quasi-boson…

We propose novel coherent-state phase concentration by probabilistic measurement-induced ampli- fication. The amplification scheme uses novel architecture, thermal noise addition (instead of single photon addition) followed by feasible…

Quantum Physics · Physics 2015-05-13 Petr Marek , Radim Filip

We present a numerical method to approximate the long-time asymptotic solution $\rho_\infty(t)$ to the Lindblad master equation for an open quantum system under the influence of an external drive. The proposed scheme uses perturbation…

Quantum Physics · Physics 2018-11-14 Brian Baker , Andy C. Y. Li , Nicholas Irons , Nathan Earnest , Jens Koch

We address the dynamics of damped collective modes in terms of first and second moments. The modes are introduced in a self-consistent fashion with the help of a suitable application of linear response theory. Quantum effects in the…

Nuclear Theory · Physics 2007-05-23 H. Hofmann , D. Kiderlen

We study vacuum quantum fluctuations of simple Nambu-Goldstone bosons - derivatively coupled single scalar-field theories possessing shift-symmetry in field space. We argue that quantum fluctuations of the interacting field can be…

High Energy Physics - Theory · Physics 2013-01-29 Alexander Vikman

Various constraints concerning control fields can be imposed in the realistic implementations of quantum control systems. One of the most important is the restriction on the frequency spectrum of acceptable control parameters. It is…

Quantum Physics · Physics 2014-02-28 Łukasz Pawela , Zbigniew Puchała

We derive the self-consistent random phase approximations (sc-RPA) from the projective truncation approximation (PTA) for the equation of motion of two-time Green's function. The obtained sc-RPA applies to arbitrary temperature and recovers…

Strongly Correlated Electrons · Physics 2026-04-21 Yue-Hong Wu , Xinguo Ren , Ning-Hua Tong

Variational algorithms may enable classically intractable simulations on near-future quantum computers. However, their potential is limited by hardware errors. It is therefore crucial to develop efficient ways to mitigate these errors.…

Quantum Physics · Physics 2019-05-29 Sam McArdle , Xiao Yuan , Simon Benjamin