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Related papers: Effective Hamiltonian with holomorphic variables

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The quantum harmonic oscillator is one of the most fundamental objects in physics. We consider the case where it is extended to an arbitrary number modes and includes all possible terms that are bilinear in the annihilation and creation…

Quantum Physics · Physics 2024-01-26 Mattias T. Johnsson , Daniel Burgarth

Most classical mechanical systems are based on dynamical variables whose values are real numbers. Energy conservation is then guaranteed if the dynamical equations are phrased in terms of a Hamiltonian function, which then leads to…

Mathematical Physics · Physics 2013-12-05 Gerard 't Hooft

Implementing quantum operations in the form of natural Hamiltonian dynamics is desirable, since they almost require no external control or feedback. In this work, we propose a NISQ-friendly quantum-classical hybrid approach to designing a…

Quantum Physics · Physics 2024-09-23 Arunava Majumder , Dylan Lewis , Akshaya Jayashankar , V. S. Prasannaa , Sougato Bose

One of the central problems in quantum theory is to characterize, detect, and quantify quantumness in terms of classical strategies. Dephasing processes, caused by non-dissipative information exchange between quantum systems and…

Quantum Physics · Physics 2019-08-23 Hong-Bin Chen , Ping-Yuan Lo , Clemens Gneiting , Joonwoo Bae , Yueh-Nan Chen , Franco Nori

Harnessing the full power of nascent quantum processors requires the efficient management of a limited number of quantum bits with finite lifetime. Hybrid algorithms leveraging classical resources have demonstrated promising initial results…

We reelaborate on a general method for diagonalizing a wide class of nonlinear Hamiltonians describing different quantum optical models. This method makes use of a nonlinear deformation of the usual su(2) algebra and when some physical…

Quantum Physics · Physics 2007-05-23 A. B. Klimov , A. Navarro , L. L. Sanchez-Soto

The response of a test particle, both for the free case and under the harmonic oscillator potential, to circularly polarized gravitational waves is investigated in a noncommutative quantum mechanical setting. The system is quantized…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Sunandan Gangopadhyay , Anirban Saha , Swarup Saha

A two-dimensional Pauli Hamiltonian describing the interaction of a neutral spin-1/2 particle with a magnetic field having axial and second order symmetries, is considered. After separation of variables, the one-dimensional matrix…

High Energy Physics - Theory · Physics 2008-11-26 M. V. Ioffe , S. Kuru , J. Negro , L . M. Nieto

It is known that a self-adjoint, time-independent hamiltonian can be defined for the quantum damped harmonic oscillator. We show here that the two vacua naturally associated to this operator, when expressed in terms of pseudo-bosonic…

Mathematical Physics · Physics 2015-05-28 Fabio Bagarello

We present a hybrid classical-quantum computing paradigm where the quantum part strictly runs within the coherence time of a quantum annealer, a method we call variational coherent quantum annealing (VCQA). It involves optimizing the…

Quantum Physics · Physics 2023-10-04 N. Barraza , G. Alvarado Barrios , I. Montalban , E. Solano , F. Albarrán-Arriagada

With our recently proposed effective Hamiltonian via Monte Carlo, we are able to compute low energy physics of quantum systems. The advantage is that we can obtain not only the spectrum of ground and excited states, but also wave functions.…

High Energy Physics - Lattice · Physics 2015-06-25 Xiang-Qian Luo , C. Q. Huang , J. Q. Jiang , H. Jirari , H. Kroeger , K. Moriarty

We introduce a family of identities that express general linear non-unitary evolution operators as a linear combination of unitary evolution operators, each solving a Hamiltonian simulation problem. This formulation can exponentially…

Quantum Physics · Physics 2025-12-16 Dong An , Andrew M. Childs , Lin Lin

We introduce a generalizable framework for learning to identify effective Hamiltonians directly from experimental data in solid-state quantum systems. Our approach is based on a physics-informed neural network architecture that embeds…

Mesoscale and Nanoscale Physics · Physics 2026-03-04 Jarosław Pawłowski , Mateusz Krawczyk

Variational hybrid quantum-classical algorithms (VHQCAs) are near-term algorithms that leverage classical optimization to minimize a cost function, which is efficiently evaluated on a quantum computer. Recently VHQCAs have been proposed for…

Quantum Physics · Physics 2020-04-07 Kunal Sharma , Sumeet Khatri , M. Cerezo , Patrick J. Coles

With physical quantum computers becoming increasingly accessible, research on their applications across various fields has advanced rapidly. In this paper, we present the first study of quantum cosmology conducted on physical quantum…

General Relativity and Quantum Cosmology · Physics 2024-10-31 Chih-Chien Erich Wang , Jiun-Huei Proty Wu

Identifying the Hamiltonian of a quantum system from experimental data is considered. General limits on the identifiability of model parameters with limited experimental resources are investigated, and a specific Bayesian estimation…

Quantum Physics · Physics 2019-10-15 S. G. Schirmer , F. C. Langbein

The Schrieffer-Wolff transformation aims to solve degenerate perturbation problems and give an effective Hamiltonian that describes the low-energy dynamics of the exact Hamiltonian in the low-energy subspace of unperturbed Hamiltonian. This…

Quantum Physics · Physics 2022-10-13 Zongkang Zhang , Yongdan Yang , Xiaosi Xu , Ying Li

We prove several new results concerning the pure quantum polynomial hierarchy (pureQPH). First, we show that QMA(2) is contained in pureQSigma2, that is, two unentangled existential provers can be simulated by competing existential and…

Quantum Physics · Physics 2025-10-09 Sabee Grewal , Dorian Rudolph

Computationally efficient and accurate quantum mechanical approximations to solve the many-electron Schr\"odinger equation are at the heart of computational materials science. In that respect the coupled cluster hierarchy of methods plays a…

Materials Science · Physics 2022-01-11 Tina N. Mihm , Tobias Schäfer , Sai Kumar Ramadugu , Andreas Grüneis , James J. Shepherd

Quantum Hamiltonians that are fine-tuned to their so-called Rokhsar-Kivelson (RK) points, first presented in the context of quantum dimer models, are defined by their representations in preferred bases in which their ground state wave…

Strongly Correlated Electrons · Physics 2007-11-30 Claudio Castelnovo , Claudio Chamon , Christopher Mudry , Pierre Pujol