Browsing by Author "Gough, John"

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  • Dabrowska, Anita; Gough, John (2016-04-01)
    We derive the filtering equation for Markovian systems undergoing homodyne measurement in the situation where the output processes being monitored are squeezed. The filtering theory applies to case where the system is ...
  • Gough, John (2015-01)
    We introduce the characteristic operator as the generalization of the usual concept of a transfer function of linear input-plant-output systems to arbitrary quantum nonlinear Markovian input-output models. This is intended ...
  • Emary, Clive; Gough, John (2014-11-26)
    We discuss control of the quantum-transport properties of a mesoscopic device by connecting it in a coherent feedback loop with a quantum-mechanical controller. We work in a scattering approach and derive results for the ...
  • Gough, John (2014-12-03)
    Quantum feedback networks have been introduced in quantum optics as a set of rules for constructing arbitrary networks of quantum mechanical systems connected by uni-directional quantum optical fields, and has allowed for ...
  • Gough, John; Zhang, Guofeng (2015-06-19)
    We give explicit constructions of quantum dynamical filters which generate nonclassical states (coherent states, cat states, shaped single and multi-photon states) of quantum optical fields as inputs to general quantum ...
  • Gough, John (2015-06)
    The aim of this paper is to derive the global Hamiltonian form for a quantum system and bath, or more generally a quantum network with multiple quantum input field connections, based on the local descriptions. We give a new ...
  • Gough, John; Nurdin, H. I. (2015-09-01)
    In this paper, we show that quantum memory for qudit states encoded in a single photon pulsed optical eld has a conceptually simple modular realization using only passive linear optics and coherent feedback. We exploit the ...
  • Gough, John; Ratiu, Tudor S.; Smolyanov, Oleg G. (2015)
    Noether’s theorem on constants of the motion of dynamical systems has recently been extended to classical dissipative systems (Markovian semi-groups) by Baez and Fong [J. Math. Phys. 54, 013301 (2013)]. We show how to ...
  • Gough, John (2016-12-05)
    The purpose of this paper is to set out the problems of modeling quantum communication and signal processing where the communication between systems is via a non-Markovian channel. This is a general feature of quantum ...
  • Gough, John (2017-01-23)
    The concept of a controlled flow of a dynamical system, especially when the controlling process feeds information back about the system, is of central importance in control engineering. In this paper we build on the ideas ...
  • Andreou, Christiana (Aberystwyth UniversityMathematical and Physical Sciences, 2013)
  • Gough, John; Zhang, Guofeng (2015-09)
    The purpose of this paper is to study the realization theory of quantum linear systems. It is shown that for a general quantum linear system its controllability and observability are equivalent and they can be checked by ...
  • Gough, John (2015-01-05)
    The derivation of a quantum Markovian model for an optomechanical system consisting of a quantum mechanical mirror interacting with quantum optical input fields via radiation pressure is a difficult problem which ultimately ...
  • Gough, John; Ratiu, Tudor S.; Smolyanov, Oleg (2015-11)
    This papers deals with connections between quantum anomalies and transformations of Feynman pseudo-measures. Mathematical objects related to the notion of the volume element in an infinite-dimensional space considered in ...
  • Gough, John; Ratiu, Tudor S.; Smolyanov, Oleg (2015-11)
    This papers deals with connections between quantum anomalies and transformations of Feynman pseudo-measures. Mathematical objects related to the notion of the volume element in an infinite-dimensional space considered in ...
  • Gough, John; Ratiu, Tudor S.; Smolyanov, Oleg (2015-11)
    Connections between quantum anomalies and transformations of pseudomeasures of the type of Feynman pseudomeasures are studied. Mathematical objects related to the notion of the volume element in an infinite-dimensional ...
  • Dabrowska, Anita; Gough, John (2016-03-23)
    We consider the quantum (trajectories) filtering equation for the case when the system is driven by Bose field inputs prepared in an arbitrary non-zero mean Gaussian state. The a posteriori evolution of the system is conditioned ...
  • Gough, John; James, Matthew R. (2017-03-08)
    We present a theory for connecting quantum Markov components into a network with quantum input processes in a Gaussian state (including thermal and squeezed). One would expect on physical grounds that the connection rules ...
  • Wildfeuer, Sebastian (Aberystwyth UniversityMathematical and Physical Sciences, 2013)
    Classical feedback control and system theory are playing an important role in modelling, controlling and analysing complex devices in many branches of engineering. Recent developments like quantum computers and miniaturisation ...
  • Gough, John (2016-12-19)
    We express the rules for forming quantum feedback networks using the Stratonovich form of quantum stochastic calculus rather than the Ito or SLH (J. E. Gough and M. R. James, “Quantum feedback networks: Hamiltonian ...