Quantum Information

Quantum mechanics redefines information and its fundamental properties. Researchers at Perimeter Institute work to understand the properties of quantum information and study which information processing tasks are feasible, and which are infeasible or impossible. This includes research in quantum cryptography, which studies the trade-off between information extraction and disturbance, and its applications. It also includes research in quantum error correction, which involves the study of methods for protecting information against decoherence. Another important side of the field is studying the application of quantum information techniques and insights to other areas of physics, including quantum foundations and condensed matter.

Displaying 1249 - 1260 of 1362

Limitations of Noisy Reversible Computations II

Michael Ben-Or Hebrew University of Jerusalem
June 15, 2007

PIRSA:07060053
Quantum Information
Introduction to recent developments in fault-tolerance

John Preskill California Institute of Technology (Caltech) - Division of Physics Mathematics & Astronomy
June 15, 2007

PIRSA:07060052
Quantum Information
Calibration Attack and Defense in Continuous Variable Quantum Key Distribution

Agnes Ferenczi
June 05, 2007

PIRSA:07060031
Quantum Information
Verifying Entanglement in Quantum Optical Systems

Hauke Haseler Institute for Quantum Computing (IQC)
June 05, 2007

PIRSA:07060030
Quantum Information
Anonymous Quantum Communication

Anne Broadbent University of Ottawa
June 05, 2007

PIRSA:07060010
Quantum Information
Lower bounds for Generalized Quantum Finite Automata

Mark Mercer McGill University
June 04, 2007

PIRSA:07060028
Quantum Information
Quantum Network Engineering

Man-Hong Yung Harvard University
June 04, 2007

PIRSA:07060027
Quantum Information
A Polarization Entangled Photon Source Based on a Modified Sagnac Interferometer

Devin Smith Institute for Quantum Computing (IQC)
June 04, 2007

PIRSA:07060026
Quantum Information
Toward a 5-qubit solid state quantum computer

Martin Laforest Institute for Quantum Computing (IQC)
June 04, 2007

PIRSA:07060025
Quantum Information
Toward a general theory of quantum games

Gus Gutowski Institute for Quantum Computing (IQC)
June 04, 2007

PIRSA:07060024
Quantum Information
Toward a quantum Fourier transform on SU(2).

Richard Low Apple Inc.
June 04, 2007

PIRSA:07060023
Quantum Information
Categorizing nonclassical phenomena: the explanatory power of epistemic restrictions and contextuality

Robert Spekkens Perimeter Institute for Theoretical Physics
June 04, 2007

PIRSA:07060037
Quantum Information

Quantum Foundations

Limitations of Noisy Reversible Computations II

Michael Ben-Or Hebrew University of Jerusalem
June 15, 2007

PIRSA:07060053
Quantum Information
Introduction to recent developments in fault-tolerance

John Preskill California Institute of Technology (Caltech) - Division of Physics Mathematics & Astronomy
June 15, 2007

PIRSA:07060052
Quantum Information
Calibration Attack and Defense in Continuous Variable Quantum Key Distribution

Agnes Ferenczi
June 05, 2007

PIRSA:07060031
Quantum Information
Verifying Entanglement in Quantum Optical Systems

Hauke Haseler Institute for Quantum Computing (IQC)
June 05, 2007

PIRSA:07060030
Quantum Information
We present an entanglement verification method for systems with underlying qubit-mode structure, which does not require full knowledge of the bi-partite density matrix. It is applied to a quantum key distribution experiment with coherent signal states and one of two different detection schemes: For heterodyne detection, it is possible to detect entanglement even in the presence of loss and noise whereas for Stokes operator measurements, entanglement verification fails.
Anonymous Quantum Communication

Anne Broadbent University of Ottawa
June 05, 2007

PIRSA:07060010
Quantum Information
We present an information-theoretically secure protocol for the transmission of a quantum state between an anonymous sender and an anonymous receiver. The anonymity is perfect and so is the privacy of the message. No assumption is made on the number of honest participants and this leads to a protocol in which a single participant can cause an abort. Unless the receiver is corrupt, the quantum state is never destroyed; thus the state is either transferred to the receiver or it remains in the hands of the sender.
Lower bounds for Generalized Quantum Finite Automata

Mark Mercer McGill University
June 04, 2007

PIRSA:07060028
Quantum Information
For most variations of Quantum finite automata (QFA), it is an open question to characterize the language recognition power of these machines. We extend several techniques used to obtain lower bounds on Kondacs and Watrous' 1-way Quantum Finite Automata to the case of Nayak's Generalized Quantum Finite Automata (GQFA). A consequence of these results is that the class of languages recognized by GQFAs is not closed under union.
Quantum Network Engineering

Man-Hong Yung Harvard University
June 04, 2007

PIRSA:07060027
Quantum Information
A Polarization Entangled Photon Source Based on a Modified Sagnac Interferometer

Devin Smith Institute for Quantum Computing (IQC)
June 04, 2007

PIRSA:07060026
Quantum Information
A new source of polarization entangled photons is presented based on a bidirectionally pumped spontaneous parametric down-conversion crystal in the loop of a Sagnac interferometer. The source is pumped with a pulsed Ti:SA laser, allowing for high photon pair production rates and the potential for multi-photon experiments. Implementation, detection, and preliminary experimental results will be discussed.
Toward a 5-qubit solid state quantum computer

Martin Laforest Institute for Quantum Computing (IQC)
June 04, 2007

PIRSA:07060025
Quantum Information
Toward a general theory of quantum games

Gus Gutowski Institute for Quantum Computing (IQC)
June 04, 2007

PIRSA:07060024
Quantum Information
Categorizing nonclassical phenomena: the explanatory power of epistemic restrictions and contextuality

Robert Spekkens Perimeter Institute for Theoretical Physics
June 04, 2007

PIRSA:07060037
Quantum Information

Quantum Foundations
Toward a quantum Fourier transform on SU(2).

Richard Low Apple Inc.
June 04, 2007

PIRSA:07060023
Quantum Information
Almost all known superpolynomial quantum speedups over classical algorithms have used the quantum Fourier transform (QFT). Most known applications of the QFT make use of the QFT over abelian groups, including Shor’s well known factoring algorithm [1]. However, the QFT can be generalised to act on non-abelian groups allowing different applications. For example, Kuperberg solves the dihedral hidden subgroup problem in subexponential time using the QFT on the dihedral group. The aim of this research is to construct an efficient QFT on SU(2). Most of the progress in constructing QFTs has come from applying ideas from classical algorithms such as subgroup adapted bases. For example, Moore et al. have applied classical ideas from e.g. to build non-abelian QFTs. Applying these ideas to infinite groups such as SU(2) requires new tools. The function must be sampled or discretised in a way so as to minimise the error. I will present some ideas based on classical algorithms which may lead to a QFT over the group SU(2) for band limited functions. There are problems with making these algorithms unitary that must be addressed and efficient methods for calculating coefficients (cf. the controlled phase gates in the abelian case) must be found.

Title	Speaker(s)	Date	Talk Type	Info link
Limitations of Noisy Reversible Computations II	Michael Ben-Or	2007-06-15	Conference	View details
Introduction to recent developments in fault-tolerance	John Preskill	2007-06-15	Conference	View details
Calibration Attack and Defense in Continuous Variable Quantum Key Distribution	Agnes Ferenczi	2007-06-05	Conference	View details
Verifying Entanglement in Quantum Optical Systems	Hauke Haseler	2007-06-05	Conference	View details
Anonymous Quantum Communication	Anne Broadbent	2007-06-05	Conference	View details
Lower bounds for Generalized Quantum Finite Automata	Mark Mercer	2007-06-04	Conference	View details
Quantum Network Engineering	Man-Hong Yung	2007-06-04	Conference	View details
A Polarization Entangled Photon Source Based on a Modified Sagnac Interferometer	Devin Smith	2007-06-04	Conference	View details
Toward a 5-qubit solid state quantum computer	Martin Laforest	2007-06-04	Conference	View details
Toward a general theory of quantum games	Gus Gutowski	2007-06-04	Conference	View details
Categorizing nonclassical phenomena: the explanatory power of epistemic restrictions and contextuality	Robert Spekkens	2007-06-04	Conference	View details
Toward a quantum Fourier transform on SU(2).	Richard Low	2007-06-04	Conference	View details

Quantum Information

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