Talks

10537 - 10548 of 19286 Results

A mechanism for vortex annihilation in two dimensional superfluid turbulence

Andrew Lucas University of Colorado Boulder

May 22, 2014

PIRSA:14050139

General Relativity & Quantum Cosmology
Are the recent IceCube events hinting at O(100) TeV decaying dark matter?

Atri Bhattacharya University of Liège

May 22, 2014

PIRSA:14050118

High Energy Physics
Positive Energy in Quantum Gravity

Lee Smolin Perimeter Institute for Theoretical Physics

May 21, 2014

PIRSA:14050126
Asymptotic safety – a quantum theory of gravity and matter

Astrid Eichhorn Universität Heidelberg

May 21, 2014

PIRSA:14050125
Phases for (analogue) spin foam models

Sebastian Steinhaus Friedrich Schiller University Jena

May 21, 2014

PIRSA:14050124
TBA

Flavio Mercati University of Naples Federico II

May 21, 2014

PIRSA:14050123
Entanglement and Edge Modes in Gauge Theory and Gravity

May 21, 2014

PIRSA:14050122
TBA

Florian Girelli University of Waterloo

May 21, 2014

PIRSA:14050121
Gauge theory of gravity and matter

Steven Kerr ThinkTank Maths Ltd.

May 21, 2014

PIRSA:14050120
Equality

Tobias Fritz Universität Innsbruck

May 21, 2014

PIRSA:14050063
New Vacuum and Representation For Loop Quantum Gravity

Bianca Dittrich Perimeter Institute for Theoretical Physics

May 21, 2014

PIRSA:14050119
Local quanta, unitary inequivalence, and vacuum entanglement

Hans Westman

May 20, 2014

PIRSA:14050117

Quantum Physics

A mechanism for vortex annihilation in two dimensional superfluid turbulence

Andrew Lucas University of Colorado Boulder

May 22, 2014

PIRSA:14050139

General Relativity & Quantum Cosmology

Recent numerical simulations [1] have suggested that two dimensional superfluid turbulence is characterized by a direct cascade of energy to small length scales, in contrast to the inverse cascade of normal fluids, where energy is transported to large length scales. This direct cascade is characterized by many vortex-antivortex annihilation events. Recent experimental work [2] on Bose-Einstein condensates appears to demonstrate qualitatively similar physics. I will discuss recent work in progress towards identifying the physical mechanism underlying this direct cascade, using techniques of effective field theory.
Are the recent IceCube events hinting at O(100) TeV decaying dark matter?

Atri Bhattacharya University of Liège

May 22, 2014

PIRSA:14050118

High Energy Physics

The IceCube detector has recently reported the observation of 28 events at previously unexplored energies. While the statistics of the observed events are still low, these events hint at the existence of a neutrino flux over and above the atmospheric neutrino background. We investigate the possibility that a significant component of the additional neutrino flux originates due to the decay of a very heavy dark matter (VHDM) particle via several possible channels into standard model particles. We show that a combination of a power law astrophysical neutrino spectrum and the neutrino flux from the decay of a DM species of mass in the range 150-400 TeV improves the fit to the observed neutrino events than that obtained from a best-fit astrophysical flux alone. Assuming the existence of an astrophysical background described by the IC best-fit, we also show that, for the decay of even heavier DM particles ($m_{\text{DM}} \sim 1$ PeV), the same observations impose significant constraints on the decay lifetimes. Allowing the astrophysical flux normalization to vary leads to modifications of these limits; however, there is still a range of dark matter mass and lifetime that is excluded by the IC results.
Positive Energy in Quantum Gravity

Lee Smolin Perimeter Institute for Theoretical Physics

May 21, 2014

PIRSA:14050126
Asymptotic safety – a quantum theory of gravity and matter

Astrid Eichhorn Universität Heidelberg

May 21, 2014

PIRSA:14050125
Phases for (analogue) spin foam models

Sebastian Steinhaus Friedrich Schiller University Jena

May 21, 2014

PIRSA:14050124
TBA

Flavio Mercati University of Naples Federico II

May 21, 2014

PIRSA:14050123
Entanglement and Edge Modes in Gauge Theory and Gravity

May 21, 2014

PIRSA:14050122
TBA

Florian Girelli University of Waterloo

May 21, 2014

PIRSA:14050121
Gauge theory of gravity and matter

Steven Kerr ThinkTank Maths Ltd.

May 21, 2014

PIRSA:14050120
Equality

Tobias Fritz Universität Innsbruck

May 21, 2014

PIRSA:14050063

Equality of two mathematical objects is a seemingly simple and well-understood concept. In this talk, I will do three things to explain why this is a misconception: I will survey different notions of equality, explain how revising the notion of equality has led to an emerging alternative foundation of mathematics called "homotopy type theory", and try to convince you that thinking about equality is relevant to your research in quantum field theory, quantum gravity or quantum foundations.
New Vacuum and Representation For Loop Quantum Gravity

Bianca Dittrich Perimeter Institute for Theoretical Physics

May 21, 2014

PIRSA:14050119
Local quanta, unitary inequivalence, and vacuum entanglement

Hans Westman

May 20, 2014

PIRSA:14050117

Quantum Physics

In this work we develop a formalism for describing localised quanta for a real-valued Klein-Gordon field in a one-dimensional box [0, R]. We quantise the field using non-stationary local modes which, at some arbitrarily chosen initial time, are completely localised within the left or the right side of the box. In this concrete set-up we directly face the problems inherent to a notion of local field excitations, usually thought of as elementary particles. Specifically, by computing the Bogoliubov coefficients relating local and standard (global) quantizations, we show that the local quantisation yields a Fock space F^L which is unitarily inequivalent to the standard one F^G. In spite of this, we find that the local creators and annihilators remain well defined in the global Fock space F^G, and so do the local number operators associated to the left and right partitions of the box. We end up with a useful mathematical toolbox to analyse and characterise local features of quantum states in F^G . Specifically, an analysis of the global vacuum state |0_G> ∈ F^G in terms of local number operators shows, as expected, the existence of entanglement between the left and right regions of the box. The local vacuum |0_L> ∈ F^L , on the contrary, has a very different character. It is neither cyclic nor separating and displays no entanglement. Further analysis shows that the global vacuum also exhibits a distribution of local excitations reminiscent, in some respects, of a thermal bath. We discuss how the mathematical tools developed herein may open new ways for the analysis of fundamental problems in local quantum field theory.

Title	Date	Collection	Type	Info
A mechanism for vortex annihilation in two dimensional superfluid turbulence	2014‑05‑22	Strong Gravity	Scientific Series	View details
Are the recent IceCube events hinting at O(100) TeV decaying dark matter?	2014‑05‑22	Particle Physics	Scientific Series	View details
Positive Energy in Quantum Gravity	2014‑05‑21	Quantum Gravity Day 2014	Conference	View details
Asymptotic safety – a quantum theory of gravity and matter	2014‑05‑21	Quantum Gravity Day 2014	Conference	View details
Phases for (analogue) spin foam models	2014‑05‑21	Quantum Gravity Day 2014	Conference	View details
TBA	2014‑05‑21	Quantum Gravity Day 2014	Conference	View details
Entanglement and Edge Modes in Gauge Theory and Gravity	2014‑05‑21	Quantum Gravity Day 2014	Conference	View details
TBA	2014‑05‑21	Quantum Gravity Day 2014	Conference	View details
Gauge theory of gravity and matter	2014‑05‑21	Quantum Gravity Day 2014	Conference	View details
Equality	2014‑05‑21	Colloquium	Scientific Series	View details
New Vacuum and Representation For Loop Quantum Gravity	2014‑05‑21	Quantum Gravity Day 2014	Conference	View details
Local quanta, unitary inequivalence, and vacuum entanglement	2014‑05‑20	Quantum Foundations	Scientific Series	View details

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Format results

A mechanism for vortex annihilation in two dimensional superfluid turbulence

Are the recent IceCube events hinting at O(100) TeV decaying dark matter?

Positive Energy in Quantum Gravity

Asymptotic safety – a quantum theory of gravity and matter

Phases for (analogue) spin foam models

TBA

Entanglement and Edge Modes in Gauge Theory and Gravity

TBA

Gauge theory of gravity and matter

Equality

New Vacuum and Representation For Loop Quantum Gravity

Local quanta, unitary inequivalence, and vacuum entanglement

A mechanism for vortex annihilation in two dimensional superfluid turbulence

Are the recent IceCube events hinting at O(100) TeV decaying dark matter?

Positive Energy in Quantum Gravity

Asymptotic safety – a quantum theory of gravity and matter

Phases for (analogue) spin foam models

TBA

Entanglement and Edge Modes in Gauge Theory and Gravity

TBA

Gauge theory of gravity and matter

Equality

New Vacuum and Representation For Loop Quantum Gravity

Local quanta, unitary inequivalence, and vacuum entanglement