Shapes of Eigenvectors for 1-D Random Schrodinger Operators following Rifkind and Virag

Speaker: 

Nishant Rangamani

Institution: 

University of California, Irvine

Time: 

Thursday, October 4, 2018 - 2:30pm to 3:30pm

Location: 

RH 340P

We will discuss the recent work by Rifkind and Virag concerning the shape of eigenvectors for the one-dimensional critical random Schrodinger operator. 

https://arxiv.org/abs/1605.00118

Poncelet’s Theorem, Paraorthogonal Polynomials and the Numerical Range of Truncated GGT matrices

Speaker: 

Barry Simon

Institution: 

Caltech

Time: 

Thursday, November 1, 2018 - 2:00pm

 

 During the last 20 years there has been a considerable literature on a collection of related mathematical topics: higher degree versions of Poncelet’s Theorem, certain measures associated to some finite Blaschke products and the numerical range of finite dimensional completely non-unitary contractions with defect index 1.  I will explain that without realizing it, the authors of these works were discussing OPUC.  This will allow us to use OPUC methods to provide illuminating proofs of some of their results and in turn to allow the insights from this literature to tell us something about OPUC.  In particular, I’ll discuss a Wendroff  theorem for POPUC.  This is joint work with Andrei Martínez-Finkelshtein  and Brian Simanek.

Isolated abelian varieties in cryptography

Speaker: 

Travis Scholl

Institution: 

UCI

Time: 

Tuesday, October 9, 2018 - 3:00pm to 4:00pm

Host: 

Location: 

RH 340P

Elliptic curve cryptography (ECC) is a widely used public key cryptosystem. The security of ECC relies on the difficulty of the elliptic curve discrete log problem (ECDLP). Isogenies are morphisms of curves that can be used to transfer instances of ECDLP between elliptic curves. Suppose that we suspect that some proportion of curves are "weak" in the sense that the ECDLP can be solved quickly. To avoid an attacker moving the ECDLP to a weak curve, we would want to use curves for which it difficult to transfer the ECDLP. In this talk we will introduce the notion of an "isolated" curve. These are curves which do not admit many computable isogenies which obstructs the transferring of the ECDLP.

Lower-tail large deviations of the KPZ equation

Speaker: 

Li-Cheng Tsai

Institution: 

Columbia University

Time: 

Tuesday, October 23, 2018 - 11:00am to 12:00pm

Host: 

Location: 

306 RH

Regarding time as a scaling parameter, we prove the one-point, lower tail Large Deviation Principle (LDP) of the KPZ equation, with an explicit rate function. This result confirms existing physics predictions. We utilize a formula from [Borodin Gorin 16] to convert LDP of the KPZ equation to calculating an exponential moment of the Airy point process, and analyze the latter via stochastic Airy operator and Riccati transform.

The geometry of the cyclotomic trace

Speaker: 

Aaron Mazel-Gee

Institution: 

USC

Time: 

Monday, April 1, 2019 - 4:00pm to 5:00pm

Host: 

Location: 

RH 340P

K-theory is a means of probing geometric objects by studying their vector bundles, i.e. parametrized families of vector spaces.  Algebraic K-theory, the version applying to varieties and schemes, is a particularly deep and far-reaching invariant, but it is notoriously difficult to compute.  The primary means of computing it is through its "cyclotomic trace" map K→TC to another theory called topological cyclic homology.  However, despite the enormous computational success of these so-called "trace methods" in algebraic K-theory computations, the algebro-geometric nature of the cyclotomic trace has remained mysterious.

In this talk, I will describe a new construction of TC that affords a precise interpretation of the cyclotomic trace at the level of derived algebraic geometry.  By the end of the talk, you will be able to take home with you a very nice and down-to-earth fact about traces of matrices.  No prior knowledge of algebraic K-theory or derived algebraic geometry will be assumed.

This represents joint work with David Ayala and Nick Rozenblyum.

Strong nonlinear instability and growth of Sobolev norms near quasiperiodic finite-gap tori of the 2D cubic NLS

Speaker: 

Zaher Hani

Institution: 

University of Michigan

Time: 

Tuesday, November 27, 2018 - 3:00pm

Location: 

RH 306

We consider a family of quasiperiodic solutions of the nonlinear Schrodinger equation on the 2-torus, namely the family of finite-gap solutions (tori). These solutions are inherited by the 2D equation from its completely integrable 1D counterpart (NLS on the circle) by considering solutions that only depend on one variable. Despite being linearly stable, we prove that these tori (under some genericness conditions) are nonlinearly unstable in the following strong sense: there exists solutions that start very close to those tori in certain Sobolev spaces, but eventually become larger than any given factor at later times. This is the first instance where (unstable) long-time nonlinear dynamics near (linearly stable) quasiperiodic tori is studied and constructed. (joint work with M. Guardia (UPC, Barcelona), E. Haus (University of Naples), M. Procesi (Roma Tre), and A. Maspero (SISSA))

Strong nonlinear instability and growth of Sobolev norms near quasiperiodic finite-gap tori of the 2D cubic NLS

Speaker: 

Zaher Hani

Institution: 

University of Michigan

Time: 

Tuesday, November 27, 2018 - 3:00pm

Location: 

RH 306

 We consider a family of quasiperiodic solutions of the nonlinear Schrodinger equation on the 2-torus, namely the family of finite-gap solutions (tori). These solutions are inherited by the 2D equation from its completely integrable 1D counterpart (NLS on the circle) by considering solutions that only depend on one variable. Despite being linearly stable, we prove that these tori (under some genericness conditions) are nonlinearly unstable in the following strong sense: there exists solutions that start very close to those tori in certain Sobolev spaces, but eventually become larger than any given factor at later times. This is the first instance where (unstable) long-time nonlinear dynamics near (linearly stable) quasiperiodic tori is studied and constructed. (joint work with M. Guardia (UPC, Barcelona), E. Haus (University of Naples), M. Procesi (Roma Tre), and A. Maspero (SISSA))

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