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In this article we explore a modification in the problem of controlling the rotation of a two level quantum system from an initial state to a final state in minimum time. Specifically we consider the case where the qubit is being weakly…

Quantum Physics · Physics 2012-11-09 Srinivas Sridharan

We consider the problem of optimally approximating an unavailable quantum state $\rho $ by the convex mixing of states drawn from a set of available states $\{ \nu_i\}$. The problem is recast to look for the least distinguishable state from…

Quantum Physics · Physics 2019-01-24 Massimiliano F. Sacchi

Precision, robustness, and efficiency are crucial aspects in the design of quantum technologies. Here, we show how genuine quantum features, together with non-Gaussianity, can be the key elements to achieve the best of these three aspects…

Quantum Physics · Physics 2026-01-21 Davide Rinaldi , Radim Filip , Dario Gerace , Giacomo Guarnieri

Quantum annealing provides a way of solving optimization problems by encoding them as Ising spin models which are implemented using physical qubits. The solution of the optimization problem then corresponds to the ground state of the…

Quantum Physics · Physics 2017-10-16 Nicholas Chancellor , Stefan Zohren , Paul A. Warburton

We consider the optimization problem for a shape cost functional $F(\Omega,f)$ which depends on a domain $\Omega$ varying in a suitable admissible class and on a "right-hand side" $f$. More precisely, the cost functional $F$ is given by an…

Optimization and Control · Mathematics 2016-05-18 José Carlos Bellido , Giuseppe Buttazzo , Bozhidar Velichkov

We consider the problem of maximizing the stored energy for a given charging duration in a quantum battery composed of a pair of spins-$1/2$ with Ising coupling starting from the spin-down state, using bounded transverse field control. We…

Quantum Physics · Physics 2024-12-24 Vasileios Evangelakos , Emmanuel Paspalakis , Dionisis Stefanatos

We investigate a multi-qubit quantum battery-charger model, focusing on its potential emulation on a superconducting qubit chip. Using a large-spin representation, we first obtain the analytical form of the energy $E_B(t)$, power $P_B(t)$…

Quantum Physics · Physics 2022-12-02 Lei Gao , Chen Cheng , Wen-Bin He , Rubem Mondaini , Xi-Wen Guan , Hai-Qing Lin

The study of topological superconductivity is largely based on the analysis of simple mean-field models that do not conserve particle number. A major open question in the field is whether the remarkable properties of these mean-field models…

Superconductivity · Physics 2024-10-23 Matthew F. Lapa , Michael Levin

A semiconductor quintuple quantum dot with two charge sensors and an additional contact to the center dot from an electron reservoir is fabricated to demonstrate the concept of scalable architecture. This design enables formation of the…

We discuss decoherence in charge qubits formed by multiple lateral quantum dots in the framework of the spin-boson model and the Born-Markov approximation. We consider the intrinsic decoherence caused by the coupling to bulk phonon modes.…

Mesoscale and Nanoscale Physics · Physics 2009-08-12 Martina Hentschel , Diego C. B. Valente , Eduardo R. Mucciolo , Harold U. Baranger

Optimal control can be used to significantly improve multi-qubit gates in quantum information processing hardware architectures based on superconducting circuit quantum electrodynamics. We apply this approach not only to dispersive gates of…

Quantum Physics · Physics 2015-05-14 R. Fisher , F. Helmer , S. J. Glaser , F. Marquardt , T. Schulte-Herbrueggen

We study the problem of finding the best approximate circuit that is the closest (in some pertinent metric) to a target circuit, and which satisfies a number of hardware constraints, like gate alphabet and connectivity. We look at the…

Quantum Physics · Physics 2021-11-29 Liam Madden , Andrea Simonetto

In this paper we look at a class of random optimization problems that arise in the forms typically known as Hopfield models. We view two scenarios which we term as the positive Hopfield form and the negative Hopfield form. For both of these…

Optimization and Control · Mathematics 2013-06-18 Mihailo Stojnic

In this research paper, the problem of optimization of a quadratic form over the convex hull generated by the corners of hypercube is attempted and solved. It is reasoned that under some conditions, the optimum occurs at the corners of…

Numerical Analysis · Computer Science 2014-01-29 Garimella Rama Murthy

As a means to solve optimization problems using quantum computers, the problem is typically recast into a Ising spin model whose ground-state is the solution of the optimization problem. An alternative to the Ising formulation is the…

Quantum Physics · Physics 2021-09-22 Martin Lanthaler , Wolfgang Lechner

This investigation is motivated by the problem of optimal design of cooling elements in modern battery systems. We consider a simple model of two-dimensional steady-state heat conduction described by elliptic partial differential equations…

Numerical Analysis · Mathematics 2013-07-05 Xiaohui Peng , Katsiaryna Niakhai , Bartosz Protas

We introduce and study the turnpike property for time-varying shapes, within the viewpoint of optimal control. We focus here on second-order linear parabolic equations where the shape acts as a source term and we seek the optimal…

Analysis of PDEs · Mathematics 2020-06-23 Gontran Lance , Emmanuel Trélat , Enrique Zuazua

We consider the problem of placing n small balls of given radius in a certain domain subject to a force f in order to minimize the compliance of the configuration. Then we let n tend to infinity and look at the asymptotics of the…

Classical Analysis and ODEs · Mathematics 2007-05-23 G. Buttazzo , F. Santambrogio , N. Varchon

In Variational Quantum Simulations, the construction of a suitable parametric quantum circuit is subject to two counteracting effects. The number of parameters should be small for the device noise to be manageable, but also large enough for…

Quantum Physics · Physics 2026-03-13 Lena Funcke , Tobias Hartung , Karl Jansen , Stefan Kühn , Manuel Schneider , Paolo Stornati

We search for translationally invariant states of qubits on a ring that maximize the nearest neighbor entanglement. This problem was initially studied by O'Connor and Wootters [Phys. Rev. A {\bf 63}, 052302 (2001)]. We first map the problem…

Quantum Physics · Physics 2009-11-11 U. V. Poulsen , T. Meyer , D. Bruss , M. Lewenstein