Quantum Physics

Displaying 1357 - 1368 of 2136

The theory of composition in physics

Lucien Hardy Perimeter Institute for Theoretical Physics
April 16, 2013

PIRSA:13040121
Quantum Physics
Continuous-variable entanglement distillation and non-commutative central limit theorems

Earl Campbell University of Sheffield
April 15, 2013

PIRSA:13040122
Quantum Physics
Classical and quantum circuit obfuscation with braids

Stephen Jordan National Institute of Standards & Technology
April 08, 2013

PIRSA:13040111
Quantum Physics
12/13 PSI - Explorations on Quantum Information Lecture 14

David Cory Institute for Quantum Computing (IQC)
April 05, 2013

PIRSA:13040037
Quantum Physics
12/13 PSI - Explorations on Quantum Information Lecture 13

David Cory Institute for Quantum Computing (IQC)
April 04, 2013

PIRSA:13040036
Quantum Physics
12/13 PSI - Explorations on Quantum Information Lecture 12

David Cory Institute for Quantum Computing (IQC)
April 03, 2013

PIRSA:13040035
Quantum Physics
12/13 PSI - Explorations on Quantum Information Lecture 11

David Cory Institute for Quantum Computing (IQC)
April 02, 2013

PIRSA:13040034
Quantum Physics
12/13 PSI - Explorations on Quantum Information Lecture 10

David Cory Institute for Quantum Computing (IQC)
April 01, 2013

PIRSA:13040033
Quantum Physics
12/13 PSI - Explorations on Quantum Information Lecture 9

David Cory Institute for Quantum Computing (IQC)
March 28, 2013

PIRSA:13030064
Quantum Physics
Quoins versus Coins

Terry Rudolph Imperial College London
March 27, 2013

PIRSA:13030000
Quantum Physics
12/13 PSI - Explorations on Quantum Information Lecture 8

David Cory Institute for Quantum Computing (IQC)
March 27, 2013

PIRSA:13030063
Quantum Physics
The Quantum Steering Ellipsoid

Sania Jevtic Imperial College London
March 26, 2013

PIRSA:13030112
Quantum Physics

The theory of composition in physics

Lucien Hardy Perimeter Institute for Theoretical Physics
April 16, 2013

PIRSA:13040121
Quantum Physics
We develop a theory for describing composite objects in physics. These can be static objects, such as tables, or things that happen in spacetime (such as a region of spacetime with fields on it regarded as being composed of smaller such regions joined together). We propose certain fundamental axioms which, it seems, should be satisfied in any theory of composition. A key axiom is the order independence axiom which says we can describe the composition of a composite object in any order. Then we provide a notation for describing composite objects that naturally leads to these axioms being satisfied. In any given physical context we are interested in the value of certain properties for the objects (such as whether the object is possible, what probability it has, how wide it is, and so on). We associate a generalized state with an object. This can be used to calculate the value of those properties we are interested in for for this object. We then propose a certain principle, the composition principle, which says that we can determine the generalized state of a composite object from the generalized states for the components by means of a calculation having the same structure as the description of the generalized state. The composition principle provides a link between description and prediction.
Continuous-variable entanglement distillation and non-commutative central limit theorems

Earl Campbell University of Sheffield
April 15, 2013

PIRSA:13040122
Quantum Physics
Entanglement distillation transforms weakly entangled noisy states into highly entangled states, a primitive to be used in quantum repeater schemes and other protocols designed for quantum communication and key distribution. In this work, we present a comprehensive framework for continuous-variable entanglement distillation schemes that convert noisy non-Gaussian states into Gaussian ones in many iterations of the protocol. Instances of these protocols include the recursive Gaussifier protocol and the pumping Gaussifier protocol. The flexibility of these protocols give rise to several beneficial trade-offs related to success probabilities or memory requirements that can be adjusted to reflect experimental specifics. Despite these protocols involving measurements, we relate the convergence in this protocols to new instances of non-commutative central limit theorems. Implications of the findings for quantum repeater schemes are discussed.
Classical and quantum circuit obfuscation with braids

Stephen Jordan National Institute of Standards & Technology
April 08, 2013

PIRSA:13040111
Quantum Physics
A circuit obfuscator is an algorithm that translates logic circuits into functionally-equivalent similarly-sized logic circuits that are hard to understand. While ad hoc obfuscators have been implemented, theoretical progress has mainly been limited to no-go results. In this work, we propose a new notion of circuit obfuscation, which we call partial indistinguishability. We then prove that, in contrast to previous definitions of obfuscation, partial indistinguishability obfuscation can be achieved by a polynomial-time algorithm. Specifically, our algorithm re-compiles the given circuit using a gate that satisfies the relations of the braid group, and then reduces to a braid normal form. Variants of our obfuscation algorithm can be applied to both classical and quantum circuits.
12/13 PSI - Explorations on Quantum Information Lecture 14

David Cory Institute for Quantum Computing (IQC)
April 05, 2013

PIRSA:13040037
Quantum Physics
12/13 PSI - Explorations on Quantum Information Lecture 13

David Cory Institute for Quantum Computing (IQC)
April 04, 2013

PIRSA:13040036
Quantum Physics
12/13 PSI - Explorations on Quantum Information Lecture 12

David Cory Institute for Quantum Computing (IQC)
April 03, 2013

PIRSA:13040035
Quantum Physics
12/13 PSI - Explorations on Quantum Information Lecture 11

David Cory Institute for Quantum Computing (IQC)
April 02, 2013

PIRSA:13040034
Quantum Physics
12/13 PSI - Explorations on Quantum Information Lecture 10

David Cory Institute for Quantum Computing (IQC)
April 01, 2013

PIRSA:13040033
Quantum Physics
12/13 PSI - Explorations on Quantum Information Lecture 9

David Cory Institute for Quantum Computing (IQC)
March 28, 2013

PIRSA:13030064
Quantum Physics
Quoins versus Coins

Terry Rudolph Imperial College London
March 27, 2013

PIRSA:13030000
Quantum Physics
Human monkeys are used to thinking about the problem of choosing from a set of objects according to some desired, biased, probability distribution. Just think about how you chose your partner(s). Even when it is easy for you to do such a sampling, it can be difficult to do a quantum sampling (Q-Sampling) of the same distribution. By Q-Sampling I mean the creation of a coherent superposition of states of such objects whose amplitudes are the (square roots of) of the specified distribution. In this talk I will discuss what we do know about this problem, why it is interesting, and will discuss how it can let us achieve tasks with quantum information that are provably impossible classically.
12/13 PSI - Explorations on Quantum Information Lecture 8

David Cory Institute for Quantum Computing (IQC)
March 27, 2013

PIRSA:13030063
Quantum Physics
The Quantum Steering Ellipsoid

Sania Jevtic Imperial College London
March 26, 2013

PIRSA:13030112
Quantum Physics
A quantum steering ellipsoid may be used to faithfully represent a density matrix ? describing two qubits A and B. The ellipsoid is the geometric set of states that Bob can steer Alice's qubit to when he implements all possible measurements on his qubit. We show how the correlations between qubits A and B manifest themselves in this paradigm, giving simple conditions for when the state is entangled, or has discord. We will also present novel features of the two qubit state that are revealed by the steering ellipsoid formalism, and show that a state corresponding to an ellipsoid with non-zero volume contains a new type of correlation.

Title	Speaker(s)	Date	Talk Type	Info link
The theory of composition in physics	Lucien Hardy	2013-04-16	Scientific Series	View details
Continuous-variable entanglement distillation and non-commutative central limit theorems	Earl Campbell	2013-04-15	Scientific Series	View details
Classical and quantum circuit obfuscation with braids	Stephen Jordan	2013-04-08	Scientific Series	View details
12/13 PSI - Explorations on Quantum Information Lecture 14	David Cory	2013-04-05	Course	View details
12/13 PSI - Explorations on Quantum Information Lecture 13	David Cory	2013-04-04	Course	View details
12/13 PSI - Explorations on Quantum Information Lecture 12	David Cory	2013-04-03	Course	View details
12/13 PSI - Explorations on Quantum Information Lecture 11	David Cory	2013-04-02	Course	View details
12/13 PSI - Explorations on Quantum Information Lecture 10	David Cory	2013-04-01	Course	View details
12/13 PSI - Explorations on Quantum Information Lecture 9	David Cory	2013-03-28	Course	View details
Quoins versus Coins	Terry Rudolph	2013-03-27	Scientific Series	View details
12/13 PSI - Explorations on Quantum Information Lecture 8	David Cory	2013-03-27	Course	View details
The Quantum Steering Ellipsoid	Sania Jevtic	2013-03-26	Scientific Series	View details

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Format results

The theory of composition in physics

Continuous-variable entanglement distillation and non-commutative central limit theorems

Classical and quantum circuit obfuscation with braids

12/13 PSI - Explorations on Quantum Information Lecture 14

12/13 PSI - Explorations on Quantum Information Lecture 13

12/13 PSI - Explorations on Quantum Information Lecture 12

12/13 PSI - Explorations on Quantum Information Lecture 11

12/13 PSI - Explorations on Quantum Information Lecture 10

12/13 PSI - Explorations on Quantum Information Lecture 9

Quoins versus Coins

12/13 PSI - Explorations on Quantum Information Lecture 8

The Quantum Steering Ellipsoid

The theory of composition in physics

Continuous-variable entanglement distillation and non-commutative central limit theorems

Classical and quantum circuit obfuscation with braids

12/13 PSI - Explorations on Quantum Information Lecture 14

12/13 PSI - Explorations on Quantum Information Lecture 13

12/13 PSI - Explorations on Quantum Information Lecture 12

12/13 PSI - Explorations on Quantum Information Lecture 11

12/13 PSI - Explorations on Quantum Information Lecture 10

12/13 PSI - Explorations on Quantum Information Lecture 9

Quoins versus Coins

12/13 PSI - Explorations on Quantum Information Lecture 8

The Quantum Steering Ellipsoid