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THE Journal Club
- Venue: Ernest Rutherford
Physics Building, room 326
- Contact: Aaron Vincent
(vincenta at physics dot mcgill dot ca)
- Wednesday, April 28th 2010, 13:30
- Holographic superconductors in string theory
- Nima Lashkari
- Papers:
Jerome P. Gauntlett, Julian Sonner, Toby Wiseman
arXiv:0907.3796
Jerome P. Gauntlett, Julian Sonner, Toby Wiseman
arXiv:0912.0512
Steven S. Gubser, Silviu S. Pufu, Fabio D. Rocha
arXiv:0908.0011
The common approach to holographic superconductors is bottom-up and based
on 4D phenomenological theories. While it is easy to see that these theories
could be generically produced at the linear level through compactification arXiv:0901.1160, a full non-linear
reduction is required to establish the holographic duality. we will discuss
the construction of holographic superconductors using consistent truncations
of M-theory on Sasaki-Einstein SE7 manifolds. Although these
embeddings have a lot in common with phenomenological models of holographic
superconductors, their low temperature limit is different.
- Wednesday, March 31st 2010, 13:30
- MSSM in view of PAMELA and Fermi-LAT
- Guy Moore
- Paper: MSSM in view of PAMELA and Fermi-LAT
Author: Borut Bajc, Tsedenbaljir Enkhbat, Dilip Kumar Ghosh, Goran Senjanovic,
Yue Zhang,
arXiv:1002.3631
What happens if the Minimal supersymmetric extension of the Standard
Model is expected to explain neutrino masses? It can, provided one
abandons R-symmetry. The paper I discuss reviews this scenario and sees
whether it can also be consistent with experimental data and whether it
can account for the alledged anomalies in astrophysical data indicating
positron excesses in the galaxy.
- Wednesday, March 17th 2010, 13:30
- N-PI Effective Actions for Thermal Field Theory
- Marcus Tassler
- The problems encountered when studying time dependent or
non-equilibrium processes in thermal QFT's has led to interest in the
application of N-Particle irreducible actions to thermal phenomena. The
purpose of my talk is to review some of the challenges and to give an overview
of the benefits and problems of this technique. For an introduction see
hep-ph/0401172. Applications
like arXiv:0906.1140 and
hep-ph/0409123 will be
discussed.
- Wednesday, March 10th 2010, 13:30
- The Kerr-Fermi Sea
- Arnaud Lepage-Jutier
- Paper: The Kerr-Fermi Sea
Author: Thomas Hartman, Wei Song, Andrew Strominger,
arXiv:0912.4265
The presence of a massive scalar field near a Kerr black hole is known
to produce instabilities associated with bound superradiant modes. In this
paper we show that for massive fermions, rather than inducing an instability,
the bound superradiant modes condense and form a Fermi sea which extends
well outside the ergosphere. The shape of this Fermi sea in phase space and
various other properties are analytically computed in the semiclassical WKB
approximation. The low energy effective theory near the black hole is described
by ripples in the Fermi surface. Expressions are derived for their dispersion
relation and the effective force on particles which venture into the sea.
- Wednesday, February 24th 2010, 13:30
- Non-Canonical Inflation: Attractors and Initial
Conditions
- Paul Franche
- Papers: Attractive Lagrangians for Non-Canonical
Inflation, arXiv:0912.1857
Initial Conditions for Non-Canonical Inflation, arXiv:1002.2639
Authors: Paul Franche, Rhiannon Gwyn, Bret Underwood, Alisha Wissanji
- Wednesday, February 17th 2010, 13:30
- Dark Matter is Exciting!
- Andrew Frey
- Most of the matter in the universe is made of invisible
particles called dark matter. After reviewing the evidence for and predictive
power of this statement, I'll sketch some common beliefs about dark matter.
Then I will describe my work investigating how new models of dark matter might
solve a mystery in particle astrophysics that is several decades old.
- Wednesday, January 27th 2010, 13:30
- Introduction to Group Field Theory
- Razvan Gurau
-
This talk is a first introduction to Group Field Theory, the higher dimensional
generalization of Random Matrix Models. As a theory of random topological
spaces of arbitrary dimensions, the naive GFT generates many pathological
topologies. They can be eliminated by considering the Colored GFT model,
which I will detail in the end of my talk.
- Wednesday, January 20th 2010, 13:30
- The origin of gravity and
the laws of Newton
- Yi Wang
- I will talk about Erik Verlinde's recent work on gravity as
an entropy force. I can't comment at this time how probable for his theory
to be true. However, if it is true, gravity becomes no longer fundamental;
it is induced from a change of entropy. Newton's second law (for gravity),
Newtonian gravity and Einstein equations can be derived and re-interpreted
from his assumption that gravity is an entropy force. Holography is needed
to derive and interpret these equations.
- Wednesday, January 13th 2010, 12:00
- Galilean Conformal Algebras
- Alejandra Castro
- Papers:
arXiv:0902.1385 and
arXiv:0912.1090
- Thursday, December 10th 2009, 12:00
- Black Holes in New Massive Gravity
- Alisha Wissanji
- Thursday, November 26th 2009, 12:00
- The Speed of Light in Lifshitz Theory
- Xue Wei
- Papers:
arXiv:0811.2217 and
arXiv:0901.3775
- Thursday, November 12th 2009, 12:00
- Cosmological constraints on axion fields
- Aaron Vincent
- Papers:
arXiv:0911.0421,
arXiv:0911.0418,
arXiv:0910.5706
- Thursday, November 5th 2009, 12:00
- String Photini at the LHC
- Guy Moore
- Authors: Arvanitaki, Craig, Dimopoulos, Dubovsky, and March-Russel,
arXiv:0909.5440
- Thursday, October 29th 2009, 12:00
- Quasi-single field inflation and non-Gaussianities
- Yi Wang
- Paper: Large non-Gaussianities with Intermediate Shapes from Quasi-Single Field Inflation
Author: Xingang Chen, Yi Wang,
arXiv:0909.0496
- Thursday, October 15th 2009, 12:00
- Oscillations in the CMB from Axion Monodromy Inflation
- Bret Underwood
- Author: Raphael Flauger, Liam McAllister, Enrico Pajer, Alexander Westphal, Gang Xu,
arXiv:0907.2916
- Thursday, October 1st 2009, 12:00
- Anisotropic Conformal Infinity
- Alejandra Castro
- Author: P. Horava and C. Melby-Thompson,
arXiv:0909.3841
- Thursday, September 24th 2009, 12:00
- Sitter space, partition functions, and other such tasty things
- Alex Maloney
- Thursday, September 17th 2009, 12:00
- Why de sitter space is not thermal
- Alex Maloney
- Thursday, September 10th 2009, 13:00
- Challenges for Horava-Lifshitz gravity
- Robert Brandenberger
- Papers:
P. Horava, arXiv:0901.3775
R. Brandenberger, arXiv:0904.2835
C. Charmousis et al, arXiv:0905.2579
X. Gao et al, arXiv:0905.3821
- Thursday, March 19th 2009, 13:00
- New particle physics models of dark matter
- Andrew Frey
- Thursday, February 19th 2009, 13:05
- Landscape of superconducting membranes
- Alisha Wissanji
-
Author: Frederik Denef and Sean A. Hartnoll,
arXiv:0901.1160
- Thursday, February 12th 2009, 13:05
- Quantum gravity at a Lifshitz point
- Mia Mohammed
-
Author: P. Horava,
arXiv:0901.3775
- Thursday, February 5th 2009, 13:05
- Monodromy in the CMB: Gravity waves and string
inflation
- Paul Franche
-
Author: E. Silverstein and A. Westphal,
arXiv:0803.3085
- Thursday, January 29th 2009, 13:05
- Brownian motion in AdS/CFT
- Nima Lashkari
-
Author: J. de Boer, V. E. Hubeny, M. Rangamani & M. Shigemori,
arXiv:0812.5112
- Thursday, January 22nd 2009, 13:35
- Confinement, turbulence and diffraction catastrophes
- Simon Caron Huot
-
Author: Blaizot and Nowak,
arXiv:0901.2284
- Thursday, January 22nd 2009, 13:05
- Standard Model Higgs boson mass from inflation
- Aaron Vincent
-
Author: Shaposhnikov, Bezrukov and Magnin,
arXiv:0812.4950
- Thursday, May 15th 2008, 13:00
- Note special venue
- Bagger-Lambert theory
- Andrew Frey
- Wednesday, April 30th 2008, 14:00
- Note special day and time
- The bulk and boundary GL(1|1) WZNW model
- Thomas Creutzig
- Lie super group Wess-Zumino-Novikov-Witten models provide
a class of conformal field theories with super group target space. In the
example of the Lie super group GL(1|1), we explain a formalism to compute
correlation functions of the bulk and boundary model. This formalism can be
generalized to all unitary Lie super groups and computation of correlation
functions can be reduced to computations in the WZNW model of the underlying
Lie group.
- Thursday, April 10th 2008, 13:00
- Could quark masses by generated from massless QCD?
- Alejandro Cabo
- Tuesday, February 12th 2008, 13:00
- Note special day and venue
- A new test of gravitational theories using double
pulsar
- René Breton
- Pulsars are among the most exotic objects populating our
Universe, having densities and magnetic field strengths far beyond those
Machievable in Earth experiments. When found orbiting another compact body,
pulsars become powerful tools to test general relativity and alternative
theories of gravity via the ultra-precise measurement of relativistic
effects imprinted on their observed orbital motion. The “double
pulsar”, the only known binary system in which both stars are
observable pulsars, has already become the classical textbook example
of such systems. Recently, modeling of unique eclipses observed in the
“double pulsar” provided us evidence of relativistic
spin precession and yielded a qualitatively new test of theories of gravity
in the strong-field regime.
- Monday, February 4th 2008, 15:00
- Note special day and time
- On tree Amplitudes in Gauge Theory and Gravity
- Simon Caron Hout
- Paper: On tree Amplitudes in Gauge Theory and Gravity
Author: Nima Arkani-Hamed and Jared Kaplan,
arXiv:0801.2385
The paper discusses tree-level scattering amplitudes in gauge
theories,
as a function of complex external momenta. A beautifully simple
analysis of their behaviour at large complex momenta is given, and used
to prove the Britto-Cachazo-Feyng-Witten (BCFW) factorization properties
of the amplitudes. Combined with the spinor representation of
amplitudes, these factorization properties are shockingly powerful: they
make it possible (and even almost trivial) to compute by hand just
about any n-point gluon amplitude, up to say n=8! Speaker will give some
examples to illustrate how this works.
- Thursday, January 24th 2008, 13:00
- Decay of Scalar Condensation in QFT
- Francis-Yan Cyr-Racine
- Paper: Decay of Scalar Condensation in Quantum Field Theory
Author: S. Matsumoto, T. Moroi,
arXiv:0709.4338
- Thursday, November 22nd 2007, 13:00
- Unparticle Physics
- Guy Moore
- References:
Georgi:
hep-ph/0703260
Fox, Rajaraman, Shirman:
hep-ph/0705.3092
Lewis: hep-ph/0710.4147
Das, Mohanty, Rao:
hep-ph/0709.2583
(maybe) Delgado, Espinosa, Quiros:
hep-ph/0707.4309
Howard Georgi has presented an interesting proposal in which standard
model particles can couple to the degrees of freedom of a conformal field
theory. Since the allowed spectrum in such a theory is continuous (instead
of having discrete allowed energy states like particles) he calls this
“unparticles”. The idea of conformal field theories,
the unparticle idea, will be presented and some of the limitations and
constraints which people have found.
- Thursday, November 8th 2007, 13:00
- Heterotic Cosmic Strings
- Rhiannon Gwyn
- Paper: Heterotic Cosmic Strings
Author: Katrin Becker, Melanie Becker, Axel Krause,
arXiv:hep-th/0510066
Fundamental heterotic strings were ruled out as candidates for cosmic
strings by Witten in 1985 (Cosmic Superstrings, Phys Lett
B153, 243, 1985. However, the possibility of obtaining cosmic strings
in a heterotic theory was resurrected by Becker, Becker and Krause. Suitable
candidates are argued to arise from wrapped branes in M theory. I'll discuss
the Becker, Becker, Krause paper which gives the argument via a tension
and stability analysis.
- Thursday, October 18th 2007, 13:00
- Rapid roll Inflation with Conformal Coupling
- Aaron Vincent
He will discuss Lev Kofman & Shinji Mukohyama's recent
paper “Rapid roll Inflation with Conformal Coupling”
(arXiv:hep-th/0709.1952v1
in which an inflationary solution is obtained for a scalar field conformally
coupled to gravity. “Fast-roll” conditions are derived
in order to get around the eta problem that usually manifests itself for
theories with a large effective inflaton mass. This is naively applied to the
KKLMMT scenario, and the authors argue that the eta problem is effectively
solved, for low-energy inflation. They conclude by discussing possible ways
of generating cosmological perturbations. - Thursday, October 11th 2007, 13:00
- Tunneling using path integral methods (cont'd)
- Andrew Frey
We will continue the discussion of tunneling in
quantum field theory, focusing on de Sitter spacetime, comparing the
approaches of Coleman & DeLuccia and Brown & E. Weinberg
(arXiv:0706.1573).
Time permitting, we'll mention the issue of resonance tunneling
discussed in arXiv:0708.4375
and arXiv:0709.0261. - Thursday, October 4th 2007, 13:00
- Tunneling using path integral methods
- Andrew Frey
We will follow Coleman's Aspects of Symmetry, The
Uses of Insantons chapter and Coleman & De Luccia. He will also
discuss a new approach to the same calculation by A. Brown & E. Weinberg
discussed in arXiv:0706.1573.
- Thursday, September 27th 2007, 13:00
- Warped Deformed Throats have Faster (Electroweak)
Phase Transitions
- Anke Knauf
- Paper: Warped Deformed Throats have Faster (Electroweak) Phase
Transitions
Authors: Babiker Hassanain, John March-Russell, Martin Schvellinger,
arXiv:0708.2060
The question is basically: can we have a Randall-Sundrum scenario at
finite temperature or will we always end up in a black hole phase? It is
based on a paper that embeds RS into the KS throat:
The Throat as a Randall-Sundrum model with Goldberger-Wise
stabilization
Felix Brummer, Arthur Hebecker, Enrico Trincherini,
hep-th/0510113
- Thursday, September 20th 2007, 13:00
- 3-dimensional Gravity (cont'd)
- Alex Maloney
- Paper: Three-Dimensional Gravity Revisited
Author: Edward Witten,
arXiv:0706.3359
- Thursday, September 13th 2007, 13:00
- 3-dimensional Gravity
- Alex Maloney
- Paper: Three-Dimensional Gravity Revisited
Author: Edward Witten,
arXiv:0706.3359
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