arXiv subjects

Claire R. Gilson

Publications and source records attributed to Claire R. Gilson.

12 recordsLinked to original sources

arXiv2020

Soliton Solutions of Noncommutative Anti-Self-Dual Yang-Mills Equations

We present exact soliton solutions of anti-self-dual Yang-Mills equations for G=GL(N) on noncommutative Euclidean spaces in four-dimension by using the Darboux transformations. Generated solutions are represented by quasideterminants of Wronski matrices in compact forms. We give special one-soliton solutions for G=GL(2) whose energy density can be real-valued. We find that the soliton solutions are the same as the commutative ones and can be interpreted as one-domain walls in four-dimension. Scattering processes of the multi-soliton solutions are also discussed.

nlin.SI↗

arXiv2019

Darboux dressing and undressing for the ultradiscrete KdV equation

We solve the direct scattering problem for the ultradiscrete Korteweg de Vries (udKdV) equation, over $\mathbb R$ for any potential with compact (finite) support, by explicitly constructing bound state and non-bound state eigenfunctions. We then show how to reconstruct the potential in the scattering problem at any time, using an ultradiscrete analogue of a Darboux transformation. This is achieved by obtaining data uniquely characterising the soliton content and the `background' from the initial potential by Darboux transformation.

math-ph↗

arXiv2018

Statistics of photon-subtracted and photon-added states

The subtraction or addition of a prescribed number of photons to a field mode does not, in general, simply shift the probability distribution by the number of subtracted or added photons. Subtraction of a photon from an initial coherent state, for example, leaves the photon statistics unchanged and the same process applied to an initial thermal state increases the mean photon number. We present a detailed analysis of the effects of the initial photon statistics on those of the state from which the photons have been subtracted or to which they have been added. Our approach is based on two closely-related moment generating functions, one well-established and one that we introduce.

quant-ph↗

arXiv2009

Bäcklund Transformations and the Atiyah-Ward ansatz for Noncommutative Anti-Self-Dual Yang-Mills Equations

We present Backlund transformations for the noncommutative anti-self-dual Yang-Mills equation where the gauge group is G=GL(2) and use it to generate a series of exact solutions from a simple seed solution. The solutions generated by this approach are represented in terms of quasideterminants. We also explain the origins of all of the ingredients of the Backlund transformations within the framework of noncommutative twistor theory. In particular we show that the generated solutions belong to a noncommutative version of the Atiyah-Ward ansatz.

hep-th↗

arXiv2009

Dromion solutions of noncommutative Davey-Stewartson equations

We consider a noncommutative version of the Davey-Stewartson equations and derive two families of quasideterminant solution via Darboux and binary Darboux transformations. These solutions can be verified by direct substitution. We then calculate the dromion solutions of the equations and obtain computer plots in a noncommutative setting.

nlin.SI↗

arXiv2008

Bäcklund Transformations for Noncommutative Anti-Self-Dual Yang-Mills Equations

We present Backlund transformations for the noncommutative anti-self-dual Yang-Mills equation where the gauge group is G=GL(2) and use it to generate a series of exact solutions from a simple seed solution. The solutions generated by this approach are represented in terms of quasideterminants and belong to a noncommutative version of the Atiyah-Ward ansatz. In commutative limit, our results coincide with those by Corrigan, Fairlie, Yates and Goddard.

nlin.SI↗

arXiv2006

Maximum Confidence Quantum Measurements

We consider the problem of discriminating between states of a specified set with maximum confidence. For a set of linearly independent states unambiguous discrimination is possible if we allow for the possibility of an inconclusive result. For linearly dependent sets an analogous measurement is one which allows us to be as confident as possible that when a given state is identified on the basis of the measurement result, it is indeed the correct state.

quant-ph↗

arXiv2002

Maximum Fidelity Retransmission of Mirror Symmetric Qubit States

In this paper we address the problem of optimal reconstruction of a quantum state from the result of a single measurement when the original quantum state is known to be a member of some specified set. A suitable figure of merit for this process is the fidelity, which is the probability that the state we construct on the basis of the measurement result is found by a subsequent test to match the original state. We consider the maximisation of the fidelity for a set of three mirror symmetric qubit states. In contrast to previous examples, we find that the strategy which minimises the probability of erroneously identifying the state does not generally maximise the fidelity.

quant-ph↗

arXiv2002

Minimum-error discrimination between three mirror-symmetric states

We present the optimal measurement strategy for distinguishing between three quantum states exhibiting a mirror symmetry. The three states live in a two-dimensional Hilbert space, and are thus overcomplete. By mirror symmetry we understand that the transformation {|+> -> |+>, |-> -> -|->} leaves the set of states invariant. The obtained measurement strategy minimizes the error probability. An experimental realization for polarized photons, realizable with current technology, is suggested.

quant-ph↗

arXiv2001

Fidelity and the communication of quantum information

We compare and contrast the error probability and fidelity as measures of the quality of the receiver's measurement strategy for a quantum communications system. The error probability is a measure of the ability to retrieve {\it classical} information and the fidelity measures the retrieval of {\it quantum} information. We present the optimal measurement strategies for maximising the fidelity given a source that encodes information on the symmetric qubit-states.

quant-ph↗

arXiv2000

Entanglement, Information and Multiparticle Quantum Operations

Collective operations on a network of spatially-separated quantum systems can be carried out using local quantum (LQ) operations, classical communication (CC) and shared entanglement (SE). Such operations can also be used to communicate classical information and establish entanglement between distant parties. We show how these facts lead to measures of the inseparability of quantum operations, and argue that a maximally-inseparable operation on 2 qubits is the SWAP operation. The generalisation of our argument to N qubit operations leads to the conclusion that permutation operations are maximally-inseparable. For even N, we find the minimum SE and CC resources which are sufficient to perform an arbitrary collective operation. These minimum resources are 2(N-1) ebits and 4(N-1) bits, and these limits can be attained using a simple teleportation-based protocol. We also obtain lower bounds on the minimum resources for the odd case. For all $N{\geq}4$, we show that the SE/CC resources required to perform an arbitrary operation are strictly greater than those that any operation can establish/communicate.

quant-ph↗

arXiv2000

Entanglement and Collective Quantum Operations

We show how shared entanglement, together with classical communication and local quantum operations, can be used to perform an arbitrary collective quantum operation upon N spatially-separated qubits. A simple teleportation-based protocol for achieving this, which requires 2(N-1) ebits of shared, bipartite entanglement and 4(N-1) classical bits, is proposed. In terms of the total required entanglement, this protocol is shown to be optimal for even N in both the asymptotic limit and for `one-shot' applications.

quant-ph↗