Colloquium

603 talks

S001

Collection TypeSeries

SubjectPhysics

Source RepositoryPIRSA

Displaying 325 - 336 of 603

Effective field theory for hydrodynamical systems

Alberto Nicolis Columbia University
March 28, 2014

PIRSA:14030121
High Energy Physics

Astrophysics
The invasion of physics by information theory

Robert Spekkens Perimeter Institute for Theoretical Physics
March 26, 2014

PIRSA:14030085
Quantum Physics
Exact results in supersymmetric gauge theories in various dimensions

Sara Pasquetti University of Milan
March 19, 2014

PIRSA:14030084
High Energy Physics
Black Holes- the Harmonic Oscillators of the 21st Century

Andrew Strominger Harvard University
March 12, 2014

PIRSA:14030104
High Energy Physics
The Unreasonable Effectiveness Of Quantum Physics in Modern Mathematics

Robbert Dijkgraaf Institute for Advanced Study (IAS)
March 05, 2014

PIRSA:14030083
Mathematical Physics
À la recherche du temps perdu - Templeton Frontiers Colloquia

Flavio Mercati University of Naples Federico II
February 26, 2014

PIRSA:14020100
General Relativity & Quantum Cosmology
The Sherrington-Kirkpatrick model and its diluted version

Dmitry Panchenko Texas A&M University
February 20, 2014

PIRSA:14020151
Mathematical Physics
Non equilibrium thermodynamic of gravitational screens

Laurent Freidel Perimeter Institute for Theoretical Physics
February 19, 2014

PIRSA:14020144
General Relativity & Quantum Cosmology

Mathematical Physics
The National Ignition Facility (NIF):Pathway to Energy Security and Physics of the Cosmos

Edward Moses Lawrence Livermore National Laboratory
February 05, 2014

PIRSA:14020098
Astrophysics
Time, Dynamics, Chaos, and the Brain

Dean Buonomano University of California, Los Angeles

January 29, 2014

PIRSA:13010117
Beyond the Standard Paradigm

Paul Langacker Institute for Advanced Study (IAS)
January 15, 2014

PIRSA:13010116
High Energy Physics
Partially Massless Gravity
December 11, 2013

PIRSA:13120005
Astrophysics

Effective field theory for hydrodynamical systems

Alberto Nicolis Columbia University
March 28, 2014

PIRSA:14030121
High Energy Physics

Astrophysics
I will review a recently proposed formalism that describes fluids and superfluids in effective field theory terms. I will then focus on applying this formalism to peculiar string-like objects that exist in fluid systems: vortex lines and vortex rings. These do not obey Newton's second law, and, as a consequence, their behavior is highly counterintuitive. I will describe how effective field theory provides us with an optimal tool to understand how they move and how they interact with one another and with sound.
The invasion of physics by information theory

Robert Spekkens Perimeter Institute for Theoretical Physics
March 26, 2014

PIRSA:14030085
Quantum Physics
When we think of a revolution in physics, we usually think of a physical theory that manages to overthrow its predecessor. There is another kind of revolution, however, that typically happens more slowly but that is often the key to achieving the first sort: it is the discovery of a novel perspective on an existing physical theory. The use of least-action principles, symmetry principles, and thermodynamic principles are good historical examples. It turns out that we can refine our understanding of many of these principles by characterizing certain properties of physical states as resources. I will discuss some of the highlights of two resource theories: the resource theory of asymmetry, which characterizes the relations among quantum states that break a symmetry; and the resource theory of athermality, which characterizes the relations among quantum states that deviate from thermal equilibrium. In particular, I will discuss how Noether's theorem does not capture all of the consequences of symmetries of the dynamics, and how the second law of thermodynamics does not capture all of the constraints on thermodynamic transitions. Finally, I will show that both asymmetry and athermality are informational resources, and that rehabilitated versions of Noether's theorem and the second law can both be understood as constraints on data processing. Considerations such as these---as well as evidence from other fronts of the invasion---make a compelling case for the revolutionary cause of reconceiving physics from an information-theoretic perspective.
Exact results in supersymmetric gauge theories in various dimensions

Sara Pasquetti University of Milan
March 19, 2014

PIRSA:14030084
High Energy Physics
One of the central challenges in theoretical physics is to develop non-perturbative methods to describe quantitatively the dynamics of strongly coupled quantum fields. Much progress in this direction has been made for theories with a higher degree of symmetry, such as conformal symmetry or supersymmetry. In recent years the method of localisation has allowed to obtain a great deal of exact results for supersymmetric gauge theories in various dimensions which has led to the discovery of new surprising correspondences such as the celebrated Alday-Gaiotto-Tachikawa correspondence. I will review some recent results which indicate that partition functions of supersymmetric theories formulated on compact manifolds can be expressed in terms of a small set of fundamental building blocks.
Black Holes- the Harmonic Oscillators of the 21st Century

Andrew Strominger Harvard University
March 12, 2014

PIRSA:14030104
High Energy Physics
In the twentieth century, many problems across all of physics were solved by perturbative methods which reduced them to harmonic oscillators. Black holes are poised to play a similar role for the problems of twenty-first century physics. They are at once the simplest and most complex objects in the physical universe. They are maximally complex in that the number of possible microstates, or entropy, of a black hole is believed to saturate a universal bound. They are maximally simple in that, according to Einstein's theory, they are featureless holes in space characterized only by their mass, charge and angular momentum. This dual relation between simplicity and complexity, as expressed in black holes, has recently been successfully applied to problems in a disparate variety of physical systems. I will give an introduction to the subject intended for a general audience.
The Unreasonable Effectiveness Of Quantum Physics in Modern Mathematics

Robbert Dijkgraaf Institute for Advanced Study (IAS)
March 05, 2014

PIRSA:14030083
Mathematical Physics
Mathematics has proven to be "unreasonably effective" in understanding nature. The fundamental laws of physics can be captured in beautiful formulae. In this lecture I want to argue for the reverse effect: Nature is an important source of inspiration for mathematics, even of the purest kind. In recent years ideas from quantum field theory, elementary particles physics and string theory have completely transformed mathematics, leading to solutions of deep problems, suggesting new invariants in geometry and topology, and, perhaps most importantly, putting modern mathematical ideas in a `natural’ context.
À la recherche du temps perdu - Templeton Frontiers Colloquia

Flavio Mercati University of Naples Federico II
February 26, 2014

PIRSA:14020100
General Relativity & Quantum Cosmology
Augustine of Hippo declared he knew what time is until someone asked him. After 16 centuries we still largely ignore the true essence of time, but we made definite progress in studying its properties. The most striking, and somewhat intuitively (and tragically) obvious one is the irreversibility of its flow. And yet, our fundamental theories are time-reversal invariant, they do not distinguish between past and future. This is usually accounted for by assuming an immensely special initial condition of the Universe, dressed with statistical arguments. In this talk, I will show how an irreversible behaviour, and with it a growth of complexity and information, can emerge from time-reversal invariant laws, without assuming any special initial condition and without thermodynamical arguments. This phenomenon is present in General Relativity, our most advanced theory of the Universe. This irreversibility will also allow me to propose a solution of another puzzle associated with time, namely the incompatibility between the quantum and the general-relativistic notions of time.
The Sherrington-Kirkpatrick model and its diluted version

Dmitry Panchenko Texas A&M University
February 20, 2014

PIRSA:14020151
Mathematical Physics
I will talk about two types of random processes -- the classical Sherrington-Kirkpatrick (SK) model of spin glasses and its diluted version. One of the main motivations in these models is to find a formula for the maximum of the process, or the free energy, in the limit when the size of the system is getting large. The answer depends on understanding the structure of the Gibbs measure in a certain sense, and this structure is expected to be described by the so called Parisi solution in the SK model and Mézard-Parisi solution in the diluted SK model. I will explain what these are and mention some results in this direction.
Non equilibrium thermodynamic of gravitational screens

Laurent Freidel Perimeter Institute for Theoretical Physics
February 19, 2014

PIRSA:14020144
General Relativity & Quantum Cosmology

Mathematical Physics
In this talk I will review the evidence for a mysterious and deep relationship between gravitational dynamics and thermodynamics. I will show how we can extend this connection to non equilibrium thermodynamics. Using the fact that the gravitational equations are fundamentally holographic, we express them in a way that shows a deep connection between gravity and the dynamics of viscous bubbles. We will explore some aspects of this surprising correspondence.
The National Ignition Facility (NIF):Pathway to Energy Security and Physics of the Cosmos

Edward Moses Lawrence Livermore National Laboratory
February 05, 2014

PIRSA:14020098
Astrophysics
NIF is the world's most energetic laser system capable of producing over 1.8 MJ and 500 TW of ultraviolet light, about 100 times more than any other operating laser of its kind. This talk describes the unprecedented experimental capabilities of NIF, its role in fundamental science, the pathway to achieving fusion ignition and energy security missions, and the status of progress in these areas.
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.
Beyond the Standard Paradigm

Paul Langacker Institute for Advanced Study (IAS)
January 15, 2014

PIRSA:13010116
High Energy Physics
I reexamine the current situation in particle and neutrino physics from a top-down perspective, discussing such underlying issues as uniqueness versus environment, minimality versus remnants, and naturalness versus tuning.
Partially Massless Gravity
December 11, 2013

PIRSA:13120005
Astrophysics
On de Sitter space, there exists a special value for the mass of a graviton for which the linear theory propagates 4 rather than 5 degrees of freedom. If a fully non-linear version of the theory exists and can be coupled to known matter, it would have interesting properties and could solve the cosmological constant problem. I will describe evidence for and obstructions to the existence of such a theory.

Title	Speaker(s)	Date	Talk Type	Info
Effective field theory for hydrodynamical systems	Alberto Nicolis	2014-03-28	Scientific Series	View details
The invasion of physics by information theory	Robert Spekkens	2014-03-26	Scientific Series	View details
Exact results in supersymmetric gauge theories in various dimensions	Sara Pasquetti	2014-03-19	Scientific Series	View details
Black Holes- the Harmonic Oscillators of the 21st Century	Andrew Strominger	2014-03-12	Scientific Series	View details
The Unreasonable Effectiveness Of Quantum Physics in Modern Mathematics	Robbert Dijkgraaf	2014-03-05	Scientific Series	View details
À la recherche du temps perdu - Templeton Frontiers Colloquia	Flavio Mercati	2014-02-26	Scientific Series	View details
The Sherrington-Kirkpatrick model and its diluted version	Dmitry Panchenko	2014-02-20	Scientific Series	View details
Non equilibrium thermodynamic of gravitational screens	Laurent Freidel	2014-02-19	Scientific Series	View details
The National Ignition Facility (NIF):Pathway to Energy Security and Physics of the Cosmos	Edward Moses	2014-02-05	Scientific Series	View details
Time, Dynamics, Chaos, and the Brain	Dean Buonomano	2014-01-29	Scientific Series	View details
Beyond the Standard Paradigm	Paul Langacker	2014-01-15	Scientific Series	View details
Partially Massless Gravity		2013-12-11	Scientific Series	View details

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Format results

Effective field theory for hydrodynamical systems

The invasion of physics by information theory

Exact results in supersymmetric gauge theories in various dimensions

Black Holes- the Harmonic Oscillators of the 21st Century

The Unreasonable Effectiveness Of Quantum Physics in Modern Mathematics

À la recherche du temps perdu - Templeton Frontiers Colloquia

The Sherrington-Kirkpatrick model and its diluted version

Non equilibrium thermodynamic of gravitational screens

The National Ignition Facility (NIF):Pathway to Energy Security and Physics of the Cosmos

Time, Dynamics, Chaos, and the Brain

Beyond the Standard Paradigm

Partially Massless Gravity

Effective field theory for hydrodynamical systems

The invasion of physics by information theory

Exact results in supersymmetric gauge theories in various dimensions

Black Holes- the Harmonic Oscillators of the 21st Century

The Unreasonable Effectiveness Of Quantum Physics in Modern Mathematics

À la recherche du temps perdu - Templeton Frontiers Colloquia

The Sherrington-Kirkpatrick model and its diluted version

Non equilibrium thermodynamic of gravitational screens

The National Ignition Facility (NIF):Pathway to Energy Security and Physics of the Cosmos

Time, Dynamics, Chaos, and the Brain

Beyond the Standard Paradigm

Partially Massless Gravity