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This paper concerns the homogenization of Schrodinger equations for non-crystalline matter, that is to say the coefficients are given by the composition of stationary functions with stochastic deformations. Two rigorous results of so-called…

Analysis of PDEs · Mathematics 2022-06-03 Vernny Ccajma , Wladimir Neves , Jean Silva

We consider a two-level atom stimulated by a coherent monochromatic laser and we study how to enhance the squeezing of the fluorescence light and of the atom itself in the presence of a Wiseman-Milburn feedback mechanism, based on the…

Quantum Physics · Physics 2009-01-21 A. Barchielli , M. Gregoratti , M. Licciardo

We present a theoretical investigation of a three-level $\Lambda$-type atom driven by a strong coherent laser and a weak stochastic field exhibiting amplitude and phase fluctuations. The stochastic field is modeled as a complex…

Quantum Physics · Physics 2025-12-29 Sajad Ahmadi , Mohsen Akbari , Shahpoor Saeidian , Ali Motazedifard

We propose and experimentally demonstrate non-destructive and noiseless removal (filtering) of vacuum states from an arbitrary set of coherent states of continuous variable systems. Errors i.e. vacuum states in the quantum information are…

Quantum Physics · Physics 2009-11-13 C. Wittmann , D. Elser , U. L. Andersen , R. Filip , P. Marek , G. Leuchs

In the solid-state circuit QED system and based on the homodyne measurement in dispersive regime, we demonstrate that a homodyne-current-based feedback can create and stabilize highly entangled two-qubit states in the presence of moderate…

Quantum Physics · Physics 2011-09-30 Zhuo Liu , Lulin Kuang , Kai Hu , Luting Xu , Suhua Wei , Lingzhen Guo , Xin-Qi Li

We consider using Hamiltonian feedback control to increase the speed at which a continuous measurement purifies (reduces) the state of a quantum system, and thus to increase the speed of the preparation of pure states. For a measurement of…

Quantum Physics · Physics 2009-08-15 Joshua Combes , Kurt Jacobs

A self-homodyne detection scheme is proposed to perform two-mode tomography on a twin-beam state at the output of a nondegenerate optical parametric amplifier. This scheme has been devised to improve the matching between the local…

Quantum Physics · Physics 2009-10-31 Giacomo M. D'Ariano , Michael Vasilyev , Prem Kumar

The Bloch sphere is a generic picture describing a coupled two-level system and the coherent dynamics of its superposition states under control of electromagnetic fields. It is commonly employed to visualise a broad variety of phenomena…

Mesoscale and Nanoscale Physics · Physics 2013-07-19 Thomas Faust , Johannes Rieger , Maximilian J. Seitner , Jörg P. Kotthaus , Eva M. Weig

We consider a simple model system supporting stable solitons in two dimensions. The system is the parametrically driven damped nonlinear Schr\"odinger equation, and the soliton stabilises for sufficiently strong damping. The purpose of this…

Pattern Formation and Solitons · Physics 2009-11-10 N. V. Alexeeva

Monitoring the fluorescent radiation of an atom unravels the master equation evolution by collapsing the atomic state into a pure state which evolves stochastically. A robust unraveling is one that gives pure states that, on average, are…

Quantum Physics · Physics 2009-11-06 H. M. Wiseman , Zoe Brady

The purpose of this paper is to study the dynamics of a quantum coherent feedback network composed of two two-level systems (qubits) driven by two counter-propagating photons, one in each input channel. The coherent feedback network…

Quantum Physics · Physics 2022-06-30 Guofeng Zhang , Yu Pan

We study the steady state of a zero-temperature Bose gas near a Feshbach or photoassociation resonance using a two-channel mean-field model that incorporates atomic and molecular condensates, as well as correlated atom pairs originating…

Other Condensed Matter · Physics 2009-11-13 Andrew Carmichael , Juha Javanainen

We consider the theory of feedback control of a Bose-Einstein condensate (BEC) confined in a harmonic trap under a continuous measurement constructed via non-destructive imaging. A filtering theory approach is used to derive a stochastic…

Quantum Physics · Physics 2009-08-07 S. S. Szigeti , M. R. Hush , A. R. R. Carvalho , J. J. Hope

We establish a separation principle for the output feedback stabilisation of state-affine systems that are observable at the stabilization target. Relying on control templates (recently introduced in [4]), that allow to approximate a…

Optimization and Control · Mathematics 2024-11-15 Ludovic Sacchelli , Lucas Brivadis , Ulysse Serres , Itaï Ben Yaacov

We present an experimental demonstration of the power of real-time feedback in quantum metrology, confirming a theoretical prediction by Wiseman regarding the superior performance of an adaptive homodyne technique for single-shot…

Quantum Physics · Physics 2007-05-23 Michael A. Armen , John K. Au , John K. Stockton , Andrew C. Doherty , Hideo Mabuchi

In this paper, we study the stabilization problem of quantum spin-1/2 systems under continuous-time measurements. In the case without feedback, we show exponential stabilization around the excited and ground state by providing a lower bound…

Quantum Physics · Physics 2019-02-12 Weichao Liang , Nina H. Amini , Paolo Mason

We introduce an ad-hoc electrodynamics with advanced and retarded Lienard-Wiechert interactions plus the dissipative Lorentz-Dirac self-interaction force. We study the covariant dynamical system of the electromagnetic two-body problem,…

Atomic Physics · Physics 2009-11-11 Jayme De Luca

We discuss the preparation of topological insulator states with fermionic ultracold atoms in optical lattices by means of measurement-based Markovian feedback control. The designed measurement and feedback operators induce an effective…

Quantum Gases · Physics 2025-10-01 Wenhua Zhao , Ling-Na Wu , Francesco Petiziol , André Eckardt

In this paper we are concerned with the stabilizability to an equilibrium point of an ensemble of non interacting half-spins. We assume that the spins are immersed in a static magnetic field, with dispersion in the Larmor frequency, and are…

Optimization and Control · Mathematics 2018-03-12 Francesca Chittaro , Jean-Paul Gauthier

Adaptive homodyne estimation of a continuously evolving optical phase using time-symmetric quantum smoothing has been demonstrated experimentally to provide superior accuracy in the phase estimate compared to adaptive or nonadaptive…

Quantum Physics · Physics 2015-09-14 Shibdas Roy , Ian R. Petersen , Elanor H. Huntington