The CTP Lunch Club meets every Friday at noon in the Cosman seminar room, 6C-442 (provided that there are sufficient speakers). A light lunch will be provided begining at 11:50am (usually pizza, however some other options may be explored).

The seminars are designed for graduate students and should be accessible to all students. First year students are particularly encouraged to attend so that they may learn about research being performed in the CTP.

Email notification of the club will be sent to the ctp-all, ctp-postdocs and ctp-students email lists as appropriate. If you wish to speak, or have suggestions about speakers and/or possible workshop topics, please contact the organizers:

Christiana Athanasiou and Nabil Iqbal

- October 5

Si-Hui Tan

Quantum Illumination

For a very long time, people have considered the problem of discriminating between two different quantum states. Since then information-theoretic ideas such as Quantum Hypothesis Testing and Quantum Chernoff Bound have been particularly well-developed. A natural extension of the field is then to apply these techniques to

detecting and imaging objects using quantum effects such as squeezing and entanglement. I shall discuss some of the techniques available to discriminate quantum states, and show how much improvement we can get by using quantum imaging instead of traditional classical imaging, even in the presence of large amounts of noise and very high loss.

- October 12

Dionysios Anninos

Some Comments on de Sitter Holography

The possibility of a de Sitter/Conformal Field Theory correspondence with its

many open questions is discussed. If time permits, we discuss the notion of

holographic renormalization group flows and their potential relation to

cosmology.

- October 19

Junegone Chay

Basic ideas of effective field theories

Effective field theories are widely used in theoretical physics. I discuss the idea of effective field theories in general and explain why they are useful. Also the application of them is explained using a few examples. I will introduce some basic material for soft-collinear effective theory and its uses in current research.

- October 26

Jacob Bernstein

A Brief Introduction to Minimal Surfaces

(With an application to general relativity)

This talk will discuss minimal surfaces--that is surfaces in a Riemannian manifold which are critical points of area. The study of such surfaces stretches back to Euler and the birth of the calculus of variations, and a beautiful and rich theory exist for minimal surfaces already in $\mathbb{R}^3$. Such minimal surfaces can be interpretated as the shape a soap film will take, a phenomenon studied by physicist Joseph Plateau in the nineteenth century. In 1979, Richard Schoen and S.T. Yau applied minimal surfaces to a more modern physical question, using them to give the first proof of the positive energy theorem of general relativity, that is that the ADM mass of an asymptotically flat space-time is non-negative (assuming the dominant energy condition). The talk will conclude with a sketch of their argument. - November 2

Amit Sever

Massless Partons Scattering Amplitudes at Strong Coupling

We will describe a string theory method to compute the strong

coupling behavior of the scattering amplitudes of gluons in planar N=4 SYM and quarks in planar N=2 SYM in the probe approximation. The seminar will be based on 0705.0303 and 0710.0393 (hep-th). - November 9

Meifeng Lin

Lattice QCD: An Introduction for Beginners

I will describe the basic ideas and techniques of lattice QCD, the only known non-perturbative method to study the low-energy properties of QCD from first principles. By introducing a discrete space-time lattice, we regulate the theory with an explicit momentum cutoff. More importantly, this discretized version of QCD can be simulated on the computers using Monte Carlo techniques, in a way similar to statistical mechanics, which then enables us to investigate many non-perturbative phenomena.

- November 16

Alessandro Torrielli

Yangians

Integrable models are often characterised by an infinite dimensional

non-abelian symmetry algebra. In many cases, this algebra forms what is called a Yangian. Such a structure has an independent life in mathematics. We will try to give a brief introduction to the physics and the mathematics of Yangians. - November 30

Ignazio Scimemi

The jet mass of the top quark

I will discuss the use of effective field theories in processes with double top production. I will show how in this framework one can define a mass for the top quark which has good theoretical properties and how we can get high precision results.

- December 7 at 1:10pm*

Xi Yin (Harvard)

Partition functions of 3d pure gravity

The three dimensional pure gravity has been conjectured to be dual to a holomorphically factorized extremal conformal field theory. As a first step of an attempt to reconstruct the dual CFT from its partition functions (on general Riemann surfaces), we compute the latter from the gravity path integral, by summing over gravitational instantons. These instantons are hyperbolic three manifolds with a conformal boundary. In particular, we conjecture an expression for the exact contribution from the instantons that are handlebodies.

- December 14

Mark Hertzberg

Inflationary Constraints on String Theory

Cosmological inflation is the leading paradigm for the early universe, and so

it is an important task to embed inflation in a fundamental microphysical

theory such as string theory. Since string theory possesses a vast landscape

of 4-dimensional theories, we would like to know which portions contain

inflation and which do not. I prove a no-go theorem that inflation and de

Sitter vacua are forbidden in an exponentially large number of infinite

families of simple and well understood compactifications of type IIA string theory. I also mention more complicated and less well understood compactifications, which may have the ingredients for our cosmology. The

presentation will be pedagogical and accessible to all, and based on 0711.2512

[hep-th].

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