English
Related papers

Related papers: Optimal control of entanglement via quantum feedba…

200 papers

Entanglement generation can be robust against noise in approaches that deliberately incorporate dissipation into the system dynamics. The presence of additional dissipation channels may, however, limit fidelity and speed of the process.…

Quantum Physics · Physics 2019-01-28 Karl P. Horn , Florentin Reiter , Yiheng Lin , Dietrich Leibfried , Christiane P. Koch

We present a formalism to derive entanglement criteria beyond the Gaussian regime that can be readily tested by only homodyne detection. The measured observable is the Einstein-Podolsky-Rosen (EPR) correlation. Its arbitrary functional form…

Quantum Physics · Physics 2015-06-03 Hyunchul Nha , Su-Yong Lee , Se-Wan Ji , M. S. Kim

This paper studies a scheme of two spatially distant oscillator systems that are connected by Gaussian fields and examines distributed entanglement generation between two continuous-mode output Gaussian fields that are radiated by the…

Quantum Physics · Physics 2012-09-27 Hendra I. Nurdin , Naoki Yamamoto

We address the experimental determination of entanglement for systems made of a pair of polarization qubits. We exploit quantum estimation theory to derive optimal estimators, which are then implemented to achieve ultimate bound to…

Quantum Physics · Physics 2015-05-27 G. Brida , I. P. Degiovanni , A. Florio , M. Genovese , P. Giorda , A. Meda , M. G. A. Paris , A. Shurupov

We show that the methods for quantification of system-environment entanglement that were recently developed for interactions that lead to pure decoherence of the system can be straightforwardly generalized to time-dependent Hamiltonians of…

Quantum Physics · Physics 2025-04-01 Małgorzata Strzałka , Radim Filip , Katarzyna Roszak

Quantifying quantum mechanical uncertainty is vital for the increasing number of experiments that reach the uncertainty limited regime. We present a method for computing tight variance uncertainty relations, i.e., the optimal…

Quantum Physics · Physics 2017-11-01 René Schwonnek , Lars Dammeier , Reinhard F. Werner

We study the effect of local unitary noise on the entanglement evolution of a two-qubit system subject to local monitoring and inter-qubit coupling. We construct a stochastic Hamiltonian by incorporating the noise into the…

Quantum Physics · Physics 2024-03-14 Dominic Shea , Alessandro Romito

We investigate how the concepts of optimal control of measurables of a system with a time dependent Hamiltonian may be mixed with the level set technique to keep the desired entity invariant. We derive sets of equations for this purpose and…

Quantum Physics · Physics 2007-05-23 Fariel Shafee

Entanglement does not correspond to any observable and its evaluation always corresponds to an estimation procedure where the amount of entanglement is inferred from the measurements of one or more proper observables. Here we address…

Quantum Physics · Physics 2009-11-13 Marco G. Genoni , Paolo Giorda , Matteo G. A. Paris

Different ways of modelling quantum control systems, formulating control problems and solving the resulting problems are considered and compared. In particular, we compare the performance of geometric and optimal control, as well as…

Quantum Physics · Physics 2008-01-08 Sonia G Schirmer , Peter J Pemberton-Ross , Xiaoting Wang

We describe an entanglement purification protocol to generate maximally entangled states with high efficiencies from two-mode squeezed states or from mixed Gaussian continuous entangled states. The protocol relies on a local quantum…

Quantum Physics · Physics 2009-10-31 Lu-Ming Duan , G. Giedke , J. I. Cirac , P. Zoller

An optimal dynamical decoupling of a quantum system coupled to a noisy environment must take into account also the imperfections of the control pulses. We present a new formalism which describes, in a closed-form expression, the evolution…

Quantum Physics · Physics 2016-10-19 Ido Almog , Gil Loewenthal , Jonathan Coslovsky , Yoav Sagi , Nir Davidson

Estimating extensive combinations of local parameters in distributed quantum systems is a central problem in quantum sensing, with applications ranging from magnetometry to timekeeping. While optimal strategies are known for sensing…

The central issue in quantum parameter estimation is to find out the optimal measurement setup that leads to the ultimate lower bound of an estimation error. We address here a question of whether a Gaussian measurement scheme can achieve…

We compute the quantum maximal correlation for bipartite Gaussian states of continuous-variable systems. Quantum maximal correlation is a measure of correlation with the monotonicity and tensorization properties that can be used to study…

Quantum Physics · Physics 2023-03-14 Salman Beigi , Saleh Rahimi-Keshari

We discuss a model of repeated measurements of position in a quantum system which is monitored for a finite amount of time with a finite instrumental error. In this framework we recover the optimum monitoring of a harmonic oscillator…

Quantum Physics · Physics 2009-10-30 Michael B. Mensky , Roberto Onofrio , Carlo Presilla

Optimal quantum control of continuous variable systems poses a formidable computational challenge because of the high-dimensional character of the system dynamics. The framework of quantum invariants can significantly reduce the complexity…

We propose an optimal control scheme for generating quantum entanglement between two optically-levitated nanoparticles in free space. Specifically, we consider that the mechanical motion frequencies of the two levitated particles are…

Quantum Physics · Physics 2025-05-20 Jinke Cao , Qi Guo , Huatang Tan

In this paper, we consider the feedback stabilization problem for N-level quantum angular momentum systems undergoing continuous-time measurements. By using stochastic and geometric control tools, we provide sufficient conditions on the…

Optimization and Control · Mathematics 2019-02-18 Weichao Liang , Nina H. Amini , Paolo Mason

If only limited control over a multiparticle quantum system is available, a viable method to characterize correlations is to perform random measurements and consider the moments of the resulting probability distribution. We present…

Quantum Physics · Physics 2021-04-23 Satoya Imai , Nikolai Wyderka , Andreas Ketterer , Otfried Gühne