Talks

9505 - 9516 of 18100 Results

Quantum cosmology in Lorentz-violating gravity

April 10, 2014

PIRSA:14040079

General Relativity & Quantum Cosmology
13/14 PSI - Explorations in Cosmology - Lecture 4

Matthew Johnson York University

April 10, 2014

PIRSA:14040044
13/14 PSI - Explorations in Particle Theory - Lecture 4

Brian Shuve Harvey Mudd College

April 10, 2014

PIRSA:14030047
A non-commuting stabilizer formalism

Xiaotong Ni Max Planck Institute for Gravitational Physics - Albert Einstein Institute (AEI)

April 09, 2014

PIRSA:14040136

Quantum Physics

General Relativity & Quantum Cosmology
Almost quantum correlations

Antonio Acin Institute of Photonic Sciences (ICFO)

April 09, 2014

PIRSA:14040065
13/14 PSI - Explorations in Cosmology - Lecture 3

Matthew Johnson York University

April 09, 2014

PIRSA:14040043
13/14 PSI - Explorations in Particle Theory - Lecture 3

Brian Shuve Harvey Mudd College

April 09, 2014

PIRSA:14030046
Beyond local causality: causation and correlation after Bell

Matthew Pusey University of York

April 08, 2014

PIRSA:14040130

Quantum Physics
Is the Milky Way Ringing?

Lawrence Widrow Queen's University

April 08, 2014

PIRSA:14040137

Astrophysics
13/14 PSI - Explorations in Cosmology - Lecture 2

Matthew Johnson York University

April 08, 2014

PIRSA:14040042
13/14 PSI - Explorations in Particle Theory - Lecture 2

Brian Shuve Harvey Mudd College

April 08, 2014

PIRSA:14030045
13/14 PSI - Explorations in Cosmology - Lecture 1

Matthew Johnson York University

April 07, 2014

PIRSA:14040041

Quantum cosmology in Lorentz-violating gravity

April 10, 2014

PIRSA:14040079

General Relativity & Quantum Cosmology

Lorentz invariance is considered a fundamental symmetry of physical theories. However, while Lorentz violations are strongly constrained in the matter sector, constraints in the gravitational sector are weaker, allowing to contemplate the idea of Lorentz-violating gravity theories. In this talk I will discuss the effects of Lorentz violations in the quantum cosmology scenario by analyzing the properties of a simple anisotropic model in the framework of Horava-Lifshitz gravity and, if time permitting, some partial results on the viability of this class of theories.
13/14 PSI - Explorations in Cosmology - Lecture 4

Matthew Johnson York University

April 10, 2014

PIRSA:14040044
13/14 PSI - Explorations in Particle Theory - Lecture 4

Brian Shuve Harvey Mudd College

April 10, 2014

PIRSA:14030047
A non-commuting stabilizer formalism

Xiaotong Ni Max Planck Institute for Gravitational Physics - Albert Einstein Institute (AEI)

April 09, 2014

PIRSA:14040136

Quantum Physics

General Relativity & Quantum Cosmology

We propose a non-commutative extension of the Pauli stabilizer formalism. The aim is to describe a class of many-body quantum states which is richer than the standard Pauli stabilizer states. In our framework, stabilizer operators are tensor products of single-qubit operators drawn from the group {\alpha I, X,S}, where \alpha=e^{i\pi/4} and S=diag(1,i). We provide techniques to efficiently compute various properties, related to e.g. bipartite entanglement, expectation values of local observables, preparation by means of quantum circuits, parent Hamiltonians etc. We also highlight significant differences compared to the Pauli stabilizer formalism. In particular we give examples of states in our formalism which cannot arise in the Pauli stabilizer formalism, such as topological models that supports non-abelian anyons. This is a joint work with O. Buerschaper and M. van den Nest.
Almost quantum correlations

Antonio Acin Institute of Photonic Sciences (ICFO)

April 09, 2014

PIRSA:14040065

Quantum theory is successfully tested in any experimental lab every day. Apart from its experimental validity, quantum theory also constitutes a robust theoretical framework: small variations of its formalism often lead to highly implausible consequences, such as violation of the no-signalling principle or a significant increase of the computational power. In fact, it has been argued that quantum theory may represent an island in theory space. We show that, at the level of correlations, quantum theory may not be as special as initially thought. In order to do so, we define the set of almost quantum correlations and prove that this set is (i) strictly larger than the set of quantum correlations but (ii) satisfies most of the information principles introduced to characterize quantum correlations, such as local orthogonality, macroscopic locality, no advantage for nonlocal computation or non-trivial communication complexity. We also provide numerical evidence that the set is compatible with information causality. Finally, we briefly discuss how the set of almost quantum correlations naturally emerges in the consistent histories approach to quantum physics.
13/14 PSI - Explorations in Cosmology - Lecture 3

Matthew Johnson York University

April 09, 2014

PIRSA:14040043
13/14 PSI - Explorations in Particle Theory - Lecture 3

Brian Shuve Harvey Mudd College

April 09, 2014

PIRSA:14030046
Beyond local causality: causation and correlation after Bell

Matthew Pusey University of York

April 08, 2014

PIRSA:14040130

Quantum Physics

There is now a remarkable mathematical theory of causation. But applying this theory to a Bell scenario implies the Bell inequalities, which are violated in experiment. We alleviate this tension by translating the basic definitions of the theory into the framework of generalised probabilistic theories. We find that a surprising number of results carry over: the d-separation criterion for conditional independence (the no-signalling principle on steroids), and even certain quantitative limits on correlations. Finally, we begin a classification of the causal structures, such as the Bell scenarios, that are "interesting" from this perspective. Joint work with Joe Henson and Raymond Lal.
Is the Milky Way Ringing?

Lawrence Widrow Queen's University

April 08, 2014

PIRSA:14040137

Astrophysics

Recent observations from three different astronomical surveys have revealed evidence for asymmetries about the Galactic midplane in the kinematics of solar neighborhood stars. These asymmetries appear, in part, as compression-rarefaction modes in the bulk motions of stars perpendicular to the midplane. I will discuss the hypothesis that these motions were caused by the recent passage of a satellite galaxy or dark matter subhalo through the Galactic disk. In short, we may be witnessing the early stages of a disk-heating event during which the Galaxy's disk relaxes to a new state after interacting with substructure from its own halo.
13/14 PSI - Explorations in Cosmology - Lecture 2

Matthew Johnson York University

April 08, 2014

PIRSA:14040042
13/14 PSI - Explorations in Particle Theory - Lecture 2

Brian Shuve Harvey Mudd College

April 08, 2014

PIRSA:14030045
13/14 PSI - Explorations in Cosmology - Lecture 1

Matthew Johnson York University

April 07, 2014

PIRSA:14040041

Title	Date	Collection	Type	Info
Quantum cosmology in Lorentz-violating gravity	2014‑04‑10	Quantum Gravity	Scientific Series	View details
13/14 PSI - Explorations in Cosmology - Lecture 4	2014‑04‑10	13/14 PSI - Explorations in Cosmology	Course	View details
13/14 PSI - Explorations in Particle Theory - Lecture 4	2014‑04‑10	13/14 PSI - Explorations in Particle Theory	Course	View details
A non-commuting stabilizer formalism	2014‑04‑09	Perimeter Institute Quantum Discussions	Scientific Series	View details
Almost quantum correlations	2014‑04‑09	Colloquium	Scientific Series	View details
13/14 PSI - Explorations in Cosmology - Lecture 3	2014‑04‑09	13/14 PSI - Explorations in Cosmology	Course	View details
13/14 PSI - Explorations in Particle Theory - Lecture 3	2014‑04‑09	13/14 PSI - Explorations in Particle Theory	Course	View details
Beyond local causality: causation and correlation after Bell	2014‑04‑08	Quantum Foundations	Scientific Series	View details
Is the Milky Way Ringing?	2014‑04‑08	Cosmology and Gravitation	Scientific Series	View details
13/14 PSI - Explorations in Cosmology - Lecture 2	2014‑04‑08	13/14 PSI - Explorations in Cosmology	Course	View details
13/14 PSI - Explorations in Particle Theory - Lecture 2	2014‑04‑08	13/14 PSI - Explorations in Particle Theory	Course	View details
13/14 PSI - Explorations in Cosmology - Lecture 1	2014‑04‑07	13/14 PSI - Explorations in Cosmology	Course	View details

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Format results

Quantum cosmology in Lorentz-violating gravity

13/14 PSI - Explorations in Cosmology - Lecture 4

13/14 PSI - Explorations in Particle Theory - Lecture 4

A non-commuting stabilizer formalism

Almost quantum correlations

13/14 PSI - Explorations in Cosmology - Lecture 3

13/14 PSI - Explorations in Particle Theory - Lecture 3

Beyond local causality: causation and correlation after Bell

Is the Milky Way Ringing?

13/14 PSI - Explorations in Cosmology - Lecture 2

13/14 PSI - Explorations in Particle Theory - Lecture 2

13/14 PSI - Explorations in Cosmology - Lecture 1

Quantum cosmology in Lorentz-violating gravity

13/14 PSI - Explorations in Cosmology - Lecture 4

13/14 PSI - Explorations in Particle Theory - Lecture 4

A non-commuting stabilizer formalism

Almost quantum correlations

13/14 PSI - Explorations in Cosmology - Lecture 3

13/14 PSI - Explorations in Particle Theory - Lecture 3

Beyond local causality: causation and correlation after Bell

Is the Milky Way Ringing?

13/14 PSI - Explorations in Cosmology - Lecture 2

13/14 PSI - Explorations in Particle Theory - Lecture 2

13/14 PSI - Explorations in Cosmology - Lecture 1