139 results found
Herrera-Marti DA, Fowler AG, Jennings D, et al., 2010, Photonic implementation for the topological cluster-state quantum computer, Vol: 82
JENNINGS D, RUDOLPH T, 2010, Entanglement and the thermodynamic arrow of time, Vol: 81
Kennedy R, Horstmeyer L, Dragan A, et al., 2010, Qubit initialization and readout with finite coherent amplitudes in cavity QED, Vol: 82
LIANG Y, HARRIGAN N, BARTLETT S, et al., 2010, Nonclassical Correlations from Randomly Chosen Local Measurements, Vol: 104
Ahmadi M, Jennings D, Rudolph T, 2010, Dynamics of a quantum reference frame undergoing selective measurements and coherent interactions, Vol: 82
JENNINGS D, RUDOLPH T, 2010, Comment on "Quantum Solution to the Arrow-of-Time Dilemma", Vol: 104
BARRETT S, BARTLETT S, DOHERTY A, et al., 2009, Transitions in the computational power of thermal states for measurement-based quantum computation, Vol: 80
BARTLETT S, RUDOLPH T, SPEKKENS R, et al., 2009, Quantum communication using a bounded-size quantum reference frame, Vol: 11
BIGGERSTAFF D, KALTENBAEK R, HAMEL D, et al., 2009, Cluster-State Quantum Computing Enhanced by High-Fidelity Generalized Measurements, Vol: 103
COSTA F, HARRIGAN N, RUDOLPH T, et al., 2009, Entanglement detection with bounded reference frames, Vol: 11
RUDOLPH T, 2009, Simple encoding of a quantum circuit amplitude as a matrix permanent, Vol: 80
JOO J, RUDOLPH T, SANDERS B, 2009, A heralded two-qutrit entangled state, Vol: 42
LAING A, RUDOLPH T, O'BRIEN J, 2009, Experimental Quantum Process Discrimination, Vol: 102
LINDNER N, RUDOLPH T, 2009, Proposal for Pulsed On-Demand Sources of Photonic Cluster State Strings, Vol: 103
JENNINGS D, DRAGAN A, BARRETT S, et al., 2009, Quantum computation via measurements on the low-temperature state of a many-body system, Vol: 80
VARNAVA M, BROWNE D, RUDOLPH T, 2008, How good must single photon sources and detectors be for efficient linear optical quantum computation?, Vol: 1
ZHANG Q, BAO X, LU C, et al., 2008, Demonstration of a scheme for the generation of "event-ready" entangled photon pairs from a single-photon source, Vol: 77
JOO J, KNIGHT P, O'BRIEN J, et al., 2007, One-way quantum computation with four-dimensional photonic qudits, Physical Review A, Vol: 76, ISSN: 1050-2947
We consider the possibility of performing linear optical quantum computations making use of extra photonic degrees of freedom. In particular, we focus on the case where we use photons as quadbits, four-dimensional photonic qudits. The basic 2-quadbit cluster state is a hyperentangled state across polarization and two spatial mode degrees of freedom. We examine the nondeterministic methods whereby such states can be created from single photons and/or Bell pairs and then give some mechanisms for performing higher-dimensional fusion gates.
Harrigan N, Rudolph T, 2007, Ontological models and the interpretation of contextuality
Studying the extent to which realism is compatible with quantum mechanicsteaches us something about the quantum mechanical universe, regardless of thevalidity of such realistic assumptions. It has also recently been appreciatedthat these kinds of studies are fruitful for questions relating to quantuminformation and computation. Motivated by this, we extend the ontological modelformalism for realistic theories to describe a set of theories emphasizing therole of measurement and preparation devices by introducing `hidden variables'to describe them. We illustrate both the ontological model formalism and ourgeneralization of it through a series of example models taken from theliterature. Our extension of the formalism allows us to quantitatively analyzethe meaning contextuality (a constraint on successful realistic theories),finding that - taken at face-value - it can be realized as a naturalinteraction between the configurations of a system and measurement device.However, we also describe a property that we call deficiency, which followsfrom contextuality, but does not admit such a natural interpretation. Looselyspeaking, deficiency breaks a symmetry between preparations and measurements inquantum mechanics. It is the property that the set of ontic states which asystem prepared in quantum state psi may actually be in, is strictly smallerthan the set of ontic states which would reveal the measurement outcome psiwith certainty.
Harrigan N, Rudolph T, Aaronson S, 2007, Representing probabilistic data via ontological models
Ontological models are attempts to quantitatively describe the results of aprobabilistic theory, such as Quantum Mechanics, in a framework exhibiting anexplicit realism-based underpinning. Unlike either the well knownquasi-probability representations, or the "r-p" vector formalism, these modelsare contextual and by definition only involve positive probabilitydistributions (and indicator functions). In this article we study how theontological model formalism can be used to describe arbitrary statistics of asystem subjected to a finite set of preparations and measurements. We presentthree models which can describe any such empirical data and then discuss how toturn an indeterministic model into a deterministic one. This raises the issueof how such models manifest contextuality, and we provide an explicit exampleto demonstrate this. In the second half of the paper we consider the issue offinding ontological models with as few ontic states as possible.
BARTLETT S, RUDOLPH T, SANDERS B, et al., 2007, Degradation of a quantum directional reference frame as a random walk, Vol: 54, Pages: 2211-2221
BARTLETT S, RUDOLPH T, SPEKKENS R, 2007, Reference frames, superselection rules, and quantum information, Vol: 79, Pages: 555-609
KIELING K, RUDOLPH T, EISERT J, 2007, Percolation, renormalization, and quantum computing with nondeterministic gates, Vol: 99
VARNAVA M, BROWNE D, RUDOLPH T, 2007, Loss tolerant linear optical quantum memory by measurement-based quantum computing, Vol: 9
AUDENAERT K, GODSIL C, ROYLE G, et al., 2007, Symmetric squares of graphs, Vol: 97, Pages: 74-90
Rudolph T, 2006, Ontological Models for Quantum Mechanics and the Kochen-Specker theorem
Certain concrete "ontological models" for quantum mechanics (models in whichmeasurement outcomes are deterministic and quantum states are equivalent toclassical probability distributions over some space of `hidden variables') areexamined. The models are generalizations of Kochen and Specker's such model fora single 2-dimensional system - in particular a model for a three dimensionalquantum system is considered in detail. Unfortunately, it appears the models donot quite reproduce the quantum mechanical statistics. They do, however, comeclose to doing so, and in as much as they simply involve probabilitydistributions over the complex projective space they do reproduce pretty mucheverything else in quantum mechanics. The Kochen-Specker theorem is examined in the light of these models, and therather mild nature of the manifested contextuality is discussed.
DOWLING M, BARTLETT S, RUDOLPH T, et al., 2006, Observing a coherent superposition of an atom and a molecule, Vol: 74
BARTLETT S, RUDOLPH T, SPEKKENS R, 2006, Dialogue concerning two views on quantum coherence: Factist and fictionist, Vol: 4, Pages: 17-43
BRUKNER C, PAUNKOVIC N, RUDOLPH T, et al., 2006, Entanglement-assisted orientation in space, Vol: 4, Pages: 365-370
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