Browsing Quantum Systems, Information and Control by Issue Date

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  • Sobolev, Andrei; Gough, John E. (2004-03-17)
    We derive the stochastic Schrödinger equation for the limit of continuous weak measurement where the observables monitored are canonical position and momentum. To this end we extend an argument due to Smolianov and Truman ...
  • Gough, John E. (2006-11-29)
    We extend the Ito -to- Stratonovich analysis or quantum stochastic differential equations, introduced by Gardiner and Collett for emission (creation), absorption (annihilation) processes, to include scattering (conservation) ...
  • Bayat, Abolfazl; Burgarth, Daniel Klaus; Mancini, Stefano; Bose, Sougato (2008-05-22)
    We investigate the multiple use of a ferromagnetic spin chain for quantum and classical communications without resetting. We find that the memory of the state transmitted during the first use makes the spin chain a ...
  • Gough, John E.; James, Matthew R. (IEEE Press, 2008-12-09)
    The purpose of this paper is to discuss how Willems’ behavioral modeling might be applied to physical systems governed by the laws of quantum physics. A quantum behavior is simply defined in terms of the evolution of ...
  • Burgarth, Daniel Klaus; Bose, Sougato; Bruder, Christoph; Giovannetti, Vittorio (2009)
    We give a sufficient criterion that guarantees that a many-body quantum system can be controlled by properly manipulating the (local) Hamiltonian of one of its subsystems. The method can be applied to a wide range of ...
  • Giovannetti, Vittorio; Burgarth, Daniel Klaus; Mancini, Stefano (2009-01-13)
    A chain of interacting spin behaves like a quantum mediator (quantum link), which allows two distant parties that control the ends of the chain to exchange quantum messages. We show that over repeated uses without resetting ...
  • Zhang, Jingfu; Burgarth, Daniel; Ditty, Michael; Ryan, Colm A.; Chandrashekar, C. M.; Laforest, Martin; Moussa, Osama; Baugh, Jonathan; Laflamme, Raymond (2009-06-16)
    We implement an iterative quantum state transfer exploiting the natural dipolar couplings in a spin chain of a liquid-crystal NMR system. During each iteration, a finite part of the amplitude of the state is transferred ...
  • Burgarth, Daniel Klaus; Maruyama, Koji (2009-10-07)
    Identifying the many-body Hamiltonian of a large quantum system is essential in understanding many physical phenomena, yet extremely difficult in general. We show that coupling strengths in networks of spin-1/2 particles ...
  • Gough, John Edward; James, Matthew R. (2009-10-13)
    The purpose of this paper is to present simple and general algebraic methods for describing series connections in quantum networks. These methods build on and generalize existing methods for series (or cascade) connections ...
  • Gough, John Edward; Wildfeuer, Sebastian (2009-10-14)
    The theory of quantum feedback networks has recently been developed with the aim of showing how quantum input-output components may be connected together so as to control, stabilize, or enhance the performance of one of ...
  • Heule, Rahel; Bruder, Christoph; Burgarth, Daniel; Stojanović, Vladimir M. (2010)
    Motivated by some recent results of quantum control theory, we discuss the feasibility of local operator control in arrays of interacting qubits modeled as isotropic Heisenberg spin chains. Acting on one of the end spins, ...
  • Gough, John Edward; Nurdin, Hendra; Wildfeuer, Sebastian (2010-01-01)
    We show that, for arbitrary quantum feedback networks consisting of several quantum mechanical components connected by quantum fields, the limit of adiabatic elimination of fast oscillator modes in the components and the ...
  • Gough, John Edward; James, Matthew R.; Nurdin, Hendra I. (2010-02-03)
    The aim of this article is to extend linear quantum dynamical network theory to include static Bogoliubov components (such as squeezers). Within this integrated quantum network theory, we provide general methods for cascade ...
  • Burgarth, Daniel; Maryuama, Koji; Murphy, Michael; Montangero, Simone; Calarco, Tommaso; Nori, Franco; Plenio, Martin B. (2010-04-22)
    We apply quantum control techniques to a long spin chain by acting only on two qubits at one of its ends, thereby implementing universal quantum computation by a combination of quantum gates on these qubits and indirect ...
  • James, Matthew R.; Gough, John Edward (2010-08-01)
    The purpose of this paper is to extend J.C. Willems' theory of dissipative systems to open quantum systems described by quantum noise models. This theory, which combines ideas from quantum physics and control theory, ...
  • Burgarth, Daniel Klaus; Giovannetti, Vittorio (2010-08-19)
    In this addendum to our paper [ D. Burgarth and V. Giovannetti Phys. Rev. Lett. 99 100501 (2007)] we prove that during the transformation that allows one to enforce control by relaxation on a quantum system, the ancillary ...
  • Gough, John Edward; Köstler, Claus Michael (2010-12-01)
    We derive the form of the Belavkin-Kushner-Stratonovich equa- tion describing the ltering of a continuous observed quantum system via non-demolition measurements when the statistics of the input eld used for the indirect ...
  • Gough, John Edward; Guta, Madalin I.; James, Matthew R.; Nurdin, Hendra I. (2011)
    Recent developments in quantum technology mean that is it now possible to manipulate systems and measure fermion elds (e.g. reservoirs of electrons) at the quantum level. This progress has motivated some recent work on ...
  • Burgarth, Daniel; Maruyama, Koji; Nori, Franco (2011-01-14)
    A number of many-body problems can be formulated using Hamiltonians that are quadratic in the creation and annihilation operators. Here, we show how such quadratic Hamiltonians can be efficiently estimated indirectly, ...
  • Köstler, Claus (2011-01-31)
    Inspired by Lehner's results on exchangeability systems in [Leh06] we define `weak conditional freeness' and `conditional freeness' for stationary processes in an operator algebraic framework of noncommutative probability. ...

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