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It is known that any two-outcome quantum measurement can be decomposed into a continuous stochastic process using a feedback loop. In this article, we characterize which of these decompositions are possible when each iteration of the…

Quantum Physics · Physics 2014-09-10 Jan Florjanczyk , Todd A. Brun

In recent decades the field of quantum computation has seen remarkable development. While much progress has been made toward the realization of a fully digital, scalable, and fault tolerant quantum computer, there are still many essential…

Quantum Physics · Physics 2025-07-31 Ian Pannemarsh

In the study of open quantum systems it is often useful to treat mixed states as pure states of a fictitious doubled system. In this work we explore the opposite approach: mapping isolated bilayer systems to open monolayer systems.…

Quantum Physics · Physics 2026-03-25 Yuan Xue , Zihan Cheng , Matteo Ippoliti

We present a computational LCHO-CI approach allowing for the simulation of exchange interactions in gated lateral quantum dot networks. The approach is based on single-particle states calculated using a linear combination of harmonic…

Mesoscale and Nanoscale Physics · Physics 2007-06-08 Irene Puerto-Gimenez , Marek Korkusinski , Pawel Hawrylak

Quantum Hamiltonian Computing is a recent approach that uses quantum systems, in particular a single molecule, to perform computational tasks. Within this approach, we present explicit methods to construct logic gates using two different…

Quantum Physics · Physics 2019-06-18 Omid Faizy Namarvar , Olivier Giraud , Bertrand Georgeot , Christian Joachim

Long-range interacting systems, while relaxing to equilibrium, often get trapped in long-lived quasistationary states which have lifetimes that diverge with the system size. In this work, we address the question of how a long-range system…

Statistical Mechanics · Physics 2013-12-04 Aurelio Patelli , Shamik Gupta , Cesare Nardini , Stefano Ruffo

The nonlocal Cahn-Hilliard equation provides a natural extension of the classical model for phase separation by incorporating long-range interactions through a singular convolution kernel. While this formulation admits a rich existence and…

Numerical Analysis · Mathematics 2026-04-22 Andrés Miniguano-Trujillo , Andrea Poiatti , Maurizio Grasselli , Benjamin Goddard , John Pearson

Linear optical networks are devices that turn classical incident modes by a linear transformation into outgoing ones. In general, the quantum version of such transformations may mix annihilation and creation operators. We derive a simple…

Quantum Physics · Physics 2009-11-10 U. Leonhardt , A. Neumaier

We study the problem of robust performance of quantum systems under structured uncertainties. A specific feature of closed (Hamiltonian) quantum systems is that their poles lie on the imaginary axis and that neither a coherent controller…

Quantum Physics · Physics 2021-10-12 S G Schirmer , F C Langbein , C A Weidner , E A Jonckheere

In this paper the local iterative Lie-Schwinger block-diagonalization method, introduced in [FP], [DFPR1], and [DFPR2] for quantum chains, is extended to higher-dimensional quantum lattice systems with Hamiltonians that can be written as…

Mathematical Physics · Physics 2022-08-15 Simone Del Vecchio , Juerg Froehlich , Alessandro Pizzo , Stefano Rossi

A powerful control method in experimental quantum computing is the use of spin echoes, employed to select a desired term in the system's internal Hamiltonian, while refocusing others. Here we address a more general problem, describing a…

Quantum Physics · Physics 2020-03-04 Gaurav Bhole , Takahiro Tsunoda , Peter J. Leek , Jonathan A. Jones

Quantum simulation presents itself as one of the biggest advantages of developing quantum computers. Simulating a quantum system classically is almost impossible beyond a certain system size whereas a controllable quantum system inherently…

Quantum Physics · Physics 2018-06-08 Ieshan Vaidya

Collective spins of large atomic samples trapped inside optical resonators can carry quantum information that can be processed in a way similar to quantum computation with continuous variables. It is shown here that by combining the…

Quantum Physics · Physics 2017-08-14 T. Opatrny

We propose dynamical control schemes for Hamiltonian simulation in many-body quantum systems that avoid instantaneous control operations and rely solely on realistic bounded-strength control Hamiltonians. Each simulation protocol consists…

Quantum Physics · Physics 2014-06-25 Adam D. Bookatz , Pawel Wocjan , Lorenza Viola

A Hamiltonian algorithm, both theoretical and numerical, to obtain the reduced equations implementing Pontryagine's Maximum Principle for singular linear-quadratic optimal control problems is presented. This algorithm is inspired on the…

Optimization and Control · Mathematics 2012-04-13 M. Delgado-Tellez , A. Ibort

It is shown that a general two-component feedback loop can be viewed as a deformed Hamiltonian system. Some of the implications of using ideas from theoretical physics to study biological processes are discussed.

Other Quantitative Biology · Quantitative Biology 2014-12-01 David S. Tourigny

We consider a repeated quantum interaction model describing a small system $\Hh_S$ in interaction with each one of the identical copies of the chain $\bigotimes_{\N^*}\C^{n+1}$, modeling a heat bath, one after another during the same short…

Probability · Mathematics 2009-02-23 Ameur Dhahri

Quantum simulation algorithms often require numerous ancilla qubits and deep circuits, prohibitive for near-term hardware. We introduce a framework for simulating quantum channels using ensembles of low-depth circuits in place of many-qubit…

Quantum Physics · Physics 2024-08-01 Joseph Peetz , Scott E. Smart , Prineha Narang

Quantum computing architectures require an accurate and efficient description in terms of many-electron states. Recent implementations include quantum dot arrays, where the ground state of a multi q-bit system can be altered by voltages…

Mesoscale and Nanoscale Physics · Physics 2022-09-27 G. A. Nemnes , T. L. Mitran , A. T. Preda , I. Ghiu , M. Marciu , A. Manolescu

Multilayer network is a potent platform which paves a way to study the interactions among entities in various networks with multiple types of relationships. In this study, the dynamics of discrete-time quantum walk on a multilayer network…

Quantum Physics · Physics 2023-10-05 M. N. Jayakody , Priodyuti Pradhan , Dana Ben Porath , E. Cohen