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Controllable quantum many-body systems are platforms for fundamental investigations into the nature of entanglement and promise to deliver computational speed-up for a broad class of algorithms and simulations. In particular, engineering…

We present an essentially exact numerical method for modelling flux qubit chains subject to charge and flux noise. We define an essentially exact method as one that introduces errors that are completely controlled such that they can be made…

Quantum Physics · Physics 2021-10-06 Matthew R. C. Fitzpatrick , Jack Raymond , Malcolm P. Kennett

The standard quantum limit bounds the precision of measurements that can be achieved by ensembles of uncorrelated particles. Fundamentally, this limit arises from the non-commuting nature of quantum mechanics, leading to the presence of…

We consider finite-dimensional many-body quantum systems described by time-independent Hamiltonians and Markovian master equations, and present a systematic method for constructing smaller-dimensional, reduced models that exactly reproduce…

Quantum Physics · Physics 2025-07-30 Tommaso Grigoletto , Yukuan Tao , Francesco Ticozzi , Lorenza Viola

We develop a scheme for engineering genuine thermal states in analog quantum simulation platforms by coupling local degrees of freedom to driven, dissipative ancilla pseudospins. We demonstrate the scheme in a many-body quantum spin lattice…

Quantum Physics · Physics 2020-06-16 Mekena Metcalf , Jonathan E. Moussa , Wibe A. de Jong , Mohan Sarovar

Quantum annealing is a computational paradigm in which optimisation problems are mapped onto the energy landscape of an interacting quantum system and explored through its dynamical evolution. By continuously transforming a simple initial…

Quantum Physics · Physics 2026-05-11 Steven Abel , Andrei Constantin , Luca A. Nutricati

Here, we develop the exact dynamics of the central spin model, modeling a finite-bath open quantum system. Particularly, two different types of interactions are investigated between the system and the bath: Heisenberg interaction with…

Quantum Physics · Physics 2025-11-11 Devvrat Tiwari , Subhashish Banerjee

Quantum simulation in its current state faces experimental overhead in terms of physical space and cooling. We propose boson sampling as an alternative compact synthetic platform performing at room temperature. Identifying the capability of…

Quantum Physics · Physics 2025-04-03 Anuprita V. Kulkarni , Vatsana Tiwari , Auditya Sharma , Ankur Raina

We present a symmetry-enabled direct quantum protocol for computing many-body Green's functions, a central tool for studying strongly correlated quantum systems. Our protocol relies only on native time evolution and straightforward…

Quantum Physics · Physics 2026-03-03 Changhao Yi , Cunlu Zhou

We present a new Python package that uses the established notion of geometric quantum complexity to numerically compute the difficulty associated with preparing a given unitary transformation on a quantum computer. The numerical procedure…

Recent advances in quantum simulators permit unitary evolution interspersed with locally resolved mid-circuit measurements. This paves the way for the observation of large-scale space-time structures in quantum trajectories and opens a…

We study the rectification of spin current in $XXZ$ chains segmented in two parts, each with a different anisotropy parameter. Using exact diagonalization and a matrix product states algorithm we find that a large rectification (of the…

Statistical Mechanics · Physics 2018-05-23 Vinitha Balachandran , Giuliano Benenti , Emmanuel Pereira , Giulio Casati , Dario Poletti

We present a Mathematica package, QSWalk, to simulate the time evaluation of Quantum Stochastic Walks (QSWs) on arbitrary directed and weighted graphs. QSWs are a generalization of continuous time quantum walks that incorporate both…

Quantum Physics · Physics 2017-06-07 Peter E. Falloon , Jeremy Rodriguez , Jingbo B. Wang

Control scenarios have been identified where the use of randomized design may substantially improve the performance of dynamical decoupling methods [L. F. Santos and L. Viola, Phys. Rev. Lett. {\bf 97}, 150501 (2006)]. Here, by focusing on…

Quantum Physics · Physics 2009-11-13 Lea F. Santos , Lorenza Viola

We study gapless quantum spin chains with spin 1/2 and 1: the Fredkin and Motzkin models. Their entangled groundstates are known exactly but not their excitation spectra. We first express the groundstates in the continuum which allows for…

Strongly Correlated Electrons · Physics 2017-10-25 Xiao Chen , Eduardo Fradkin , William Witczak-Krempa

TEMPO (Time-dependent Evolution of Multiple Pulse Operations) offers accessible and efficient simulations of pulse sequences in Python, using the suite of master equation solvers available in the Quantum Toolbox in Python (QuTiP). It…

Quantum Physics · Physics 2025-02-18 Jner Tzern Oon , Sonja A. Hakala , George A. Witt , Ronald Walsworth

Quantum Heisenberg spin chains with random couplings and spin sizes are studied using a real-space renormalization group technique. These systems belong to a new universality class of disordered quantum spin systems realized in {\it e.g.}…

Condensed Matter · Physics 2009-10-28 E. Westerberg , A. Furusaki , M. Sigrist , P. A. Lee

The transport of conserved quantities like spin and charge is fundamental to characterizing the behavior of quantum many-body systems. Numerically simulating such dynamics is generically challenging, which motivates the consideration of…

Quantum Physics · Physics 2024-12-04 I-Chi Chen , Klée Pollock , Yong-Xin Yao , Peter P. Orth , Thomas Iadecola

Systems of interacting quantum spins show a rich spectrum of quantum phases and display interesting many-body dynamics. Computing characteristics of even small systems on conventional computers poses significant challenges. A quantum…

We present an algorithm for the simulation of the exact real-time dynamics of classical many-body systems with discrete energy levels. In the same spirit of kinetic Monte Carlo methods, a stochastic solution of the master equation is found,…

Statistical Mechanics · Physics 2016-07-20 Alejandro Mendoza-Coto , Rogelio Díaz-Méndez , Guido Pupillo