Talks

9685 - 9696 of 16758 Results

Emergence and Entanglement: A New World of Condensed Matter Physics

Xiao-Gang Wen Massachusetts Institute of Technology (MIT) - Department of Physics

January 30, 2014

PIRSA:14010108
Black hole entropy and the case for self-dual loop quantum gravity

January 29, 2014

PIRSA:14010098

Quantum Gravity
Time, Dynamics, Chaos, and the Brain

Dean Buonomano University of California, Los Angeles

January 29, 2014

PIRSA:13010117
13/14 PSI - Cosmology Review - Lecture 3

Latham Boyle University of Edinburgh

January 29, 2014

PIRSA:14010067
13/14 PSI - String Theory Review - Lecture 3

Davide Gaiotto Perimeter Institute for Theoretical Physics

January 29, 2014

PIRSA:14010072
13/14 PSI - Condensed Matter Review - Lecture 3

Alioscia Hamma University of Naples Federico II

January 29, 2014

PIRSA:14010077
Introduction to Quantum Field Theory for Cosmology - Lecture 7

Achim Kempf University of Waterloo

January 28, 2014

PIRSA:14010003
Mayer-Cluster Expansion of Instanton Partition Functions and Thermodynamic Bethe Ansatz

Carlo Meneghelli University of Oxford

January 28, 2014

PIRSA:14010096

Quantum Fields and Strings
13/14 PSI - Cosmology Review - Lecture 2

Latham Boyle University of Edinburgh

January 28, 2014

PIRSA:14010066
New light on 21cm intensity fluctuations from the dark ages

January 28, 2014

PIRSA:14010097

Cosmology
13/14 PSI - String Theory Review - Lecture 2

Davide Gaiotto Perimeter Institute for Theoretical Physics

January 28, 2014

PIRSA:14010071
13/14 PSI - Condensed Matter Review - Lecture 2

Alioscia Hamma University of Naples Federico II

January 28, 2014

PIRSA:14010076

Emergence and Entanglement: A New World of Condensed Matter Physics

Xiao-Gang Wen Massachusetts Institute of Technology (MIT) - Department of Physics

January 30, 2014

PIRSA:14010108
Black hole entropy and the case for self-dual loop quantum gravity

January 29, 2014

PIRSA:14010098

Quantum Gravity

By focusing on aspects of black hole thermodynamics, I will present some evidences supporting the unexpected role of the complex self-dual variables in quantum gravity. This will also be the occasion of revisiting some aspects of three-dimensional gravity, and in particular the link between the BTZ black hole and the Turaev-Viro state sum model. Also the information on the website for next week needs to be modified: We will not have a seminar on Thursday (as Thursday is PI day). Instead, we will have the seminar on Wednesday, but actually would prefer a different time, namely 3.30 pm.
Time, Dynamics, Chaos, and the Brain

Dean Buonomano University of California, Los Angeles

January 29, 2014

PIRSA:13010117

Time poses a fundamental problem in neuroscience, in part, because at its core the brain is a prediction machine: the brain evolved to allow animals to anticipate, adapt, and prepare for future events. To accomplish this function the brain tells time on scales spanning 12 orders of magnitude. In contrast to most man made clocks that share a very simply underlying principle-counting the "tics" of an oscillator-evolution has devised many different solutions to the problem of telling time. On the scale of milliseconds and seconds experimental and computational evidence suggests that the brain relies on neural dynamics to tell time. For this strategy to work two conditions have to be met: the states of the neural network must evolve in a nonrepeating pattern over the relevant interval, and the sequence of states must be reproducible every time the system is reengaged. Recurrently connected networks of neurons can generate rich dynamics, but a long standing challenge is that the regimes that create computationally powerful dynamics are chaotic-and thus cannot generate reproducible patterns. We have recently demonstrated that by tuning the weights (the coupling coefficients) between the units of artificial neural networks it is possible to generate locally stable trajectories embedded within chaotic attractors. These stable patterns function as "dynamic attractors" and can be used to encode and tell time. They also exhibit a novel feature characteristic of biological systems: the ability to autonomously "return" to the pattern being generated in the face of perturbations.
13/14 PSI - Cosmology Review - Lecture 3

Latham Boyle University of Edinburgh

January 29, 2014

PIRSA:14010067
13/14 PSI - String Theory Review - Lecture 3

Davide Gaiotto Perimeter Institute for Theoretical Physics

January 29, 2014

PIRSA:14010072
13/14 PSI - Condensed Matter Review - Lecture 3

Alioscia Hamma University of Naples Federico II

January 29, 2014

PIRSA:14010077
Introduction to Quantum Field Theory for Cosmology - Lecture 7

Achim Kempf University of Waterloo

January 28, 2014

PIRSA:14010003
Mayer-Cluster Expansion of Instanton Partition Functions and Thermodynamic Bethe Ansatz

Carlo Meneghelli University of Oxford

January 28, 2014

PIRSA:14010096

Quantum Fields and Strings

In arXiv:0908.4052, Nekrasov and Shatashvili pointed out that the N=2 instanton partition function in a special limit of the Omega-deformation parameters is characterized by certain thermodynamic Bethe ansatz (TBA) like equations.In this talk I will present an explicit derivation of this fact as well as generalizations to quiver gauge theories. The TBA equations derived entirely within gauge theory have been proposed to encode the spectrum of a large class of quantum integrable systems. I will conclude with some remarks on this correspondence.
13/14 PSI - Cosmology Review - Lecture 2

Latham Boyle University of Edinburgh

January 28, 2014

PIRSA:14010066
New light on 21cm intensity fluctuations from the dark ages

January 28, 2014

PIRSA:14010097

Cosmology

Fluctuations of the 21 cm brightness temperature before the formation of the first stars hold the promise of becoming a high-precision cosmological probe in the future. The growth of over densities is very well described by perturbation theory at that epoch and the signal can in principle be predicted to arbitrary accuracy for given cosmological parameters. Recently, Tseliakhovich and Hirata pointed out a previously neglected and important physical effect, due to the fact that baryons and cold dark matter (CDM) have supersonic relative velocities after recombination. This relative velocity suppresses the growth of matter fluctuations on scales k∼10−10^3 Mpc^−1. In addition, the amplitude of the small-scale power spectrum is modulated on the large scales over which the relative velocity varies, corresponding to k∼0.005−1 Mpc^−1. In this talk, I will describe the effect of the relative velocity on 21 cm brightness temperature fluctuations from redshifts z≥30. I will show that the 21 cm power spectrum is affected on most scales. On small scales, the signal is typically suppressed several tens of percent, except for extremely small scales (k≳2000 Mpc−1) for which the fluctuations are boosted by resonant excitation of acoustic waves. On large scales, 21 cm fluctuations are enhanced due to the non-linear dependence of the brightness temperature on the underlying gas density and temperature. The enhancement of the 21 cm power spectrum is of a few percent at k∼0.1 Mpc−1 and up to tens of percent at k≲0.005 Mpc−1, for standard ΛCDM cosmology. In principle this effect allows to probe the small-scale matter power spectrum not only through a measurement of small angular scales but also through its effect on large angular scales.
13/14 PSI - String Theory Review - Lecture 2

Davide Gaiotto Perimeter Institute for Theoretical Physics

January 28, 2014

PIRSA:14010071
13/14 PSI - Condensed Matter Review - Lecture 2

Alioscia Hamma University of Naples Federico II

January 28, 2014

PIRSA:14010076

Title	Date	Collection	Type	Info
Emergence and Entanglement: A New World of Condensed Matter Physics	2014‑01‑30	PI Day 2014	Conference	View details
Black hole entropy and the case for self-dual loop quantum gravity	2014‑01‑29	Quantum Gravity	Scientific Series	View details
Time, Dynamics, Chaos, and the Brain	2014‑01‑29	Colloquium	Scientific Series	View details
13/14 PSI - Cosmology Review - Lecture 3	2014‑01‑29	13/14 PSI - Cosmology Review	Course	View details
13/14 PSI - String Theory Review - Lecture 3	2014‑01‑29	13/14 PSI - String Theory Review	Course	View details
13/14 PSI - Condensed Matter Review - Lecture 3	2014‑01‑29	13/14 PSI - Condensed Matter Review	Course	View details
Introduction to Quantum Field Theory for Cosmology - Lecture 7	2014‑01‑28	Quantum Field Theory for Cosmology - 2014	Course	View details
Mayer-Cluster Expansion of Instanton Partition Functions and Thermodynamic Bethe Ansatz	2014‑01‑28	Quantum Fields and Strings	Scientific Series	View details
13/14 PSI - Cosmology Review - Lecture 2	2014‑01‑28	13/14 PSI - Cosmology Review	Course	View details
New light on 21cm intensity fluctuations from the dark ages	2014‑01‑28	Cosmology and Gravitation	Scientific Series	View details
13/14 PSI - String Theory Review - Lecture 2	2014‑01‑28	13/14 PSI - String Theory Review	Course	View details
13/14 PSI - Condensed Matter Review - Lecture 2	2014‑01‑28	13/14 PSI - Condensed Matter Review	Course	View details

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