2020
Jan
21

# Sebastian Barbieri (Bordeaux)

2:00pm to 3:00pm

2020
Jan
21

2:00pm to 3:00pm

2019
Nov
05

2:00pm to 3:00pm

Abstract:

We consider a locally finite (Radon) measure on SO(d,1)/Gamma

invariant under a horospherical subgroup of SO(d,1) where Gamma is a discrete, but not necessarily geometrically finite, subgroup. We show that whenever the measure does not observe any additional invariance properties then it must be supported on a set of points with geometrically degenerate trajectories under the corresponding contracting 1-parameter diagonalizable flow (geodesic flow). This is joint work with Elon Lindenstrauss.

We consider a locally finite (Radon) measure on SO(d,1)/Gamma

invariant under a horospherical subgroup of SO(d,1) where Gamma is a discrete, but not necessarily geometrically finite, subgroup. We show that whenever the measure does not observe any additional invariance properties then it must be supported on a set of points with geometrically degenerate trajectories under the corresponding contracting 1-parameter diagonalizable flow (geodesic flow). This is joint work with Elon Lindenstrauss.

2020
Jan
07

2020
Mar
26

2020
Mar
19

2020
Apr
02

2019
Nov
24

Repeats every week every Sunday until Sat Feb 01 2020 except Sun Oct 27 2019.

4:00pm to 6:00pmRoss 70

Tomer Schlank "Prismatic cohomology" (after Bhatt and Scholze)

Abstract: We shall discuss (Weil) cohomology theories for algebraic varieties.

When working with schemes over p-complete rings and taking cohomologies with p-complete coefficients one gets a plurality of such cohomology theories (e'tale, De-Rahm, Crystalline, etc.. ). The comparison between these different cohomology theories is a subtle subject known as "p-adic hodge theory" .

Abstract: We shall discuss (Weil) cohomology theories for algebraic varieties.

When working with schemes over p-complete rings and taking cohomologies with p-complete coefficients one gets a plurality of such cohomology theories (e'tale, De-Rahm, Crystalline, etc.. ). The comparison between these different cohomology theories is a subtle subject known as "p-adic hodge theory" .

2019
Nov
24

Repeats every week every Sunday until Sat Feb 01 2020 except Sun Oct 27 2019.

11:00am to 1:00pmRoss 70

Elon Lindenstrauss "Arithmetic applications of diagonal flows"

I will give an introduction to the dynamics of higher rank diagonal flows on homogeneous spaces,

including both the rigidity theorems of such flows and their applications to orbits of arithmetic interest,

in particular CM points and integer points on spheres.

I hope to cover parts of the following papers:

Einsiedler, Manfred ; Lindenstrauss, Elon ; Michel, Philippe ; Venkatesh, Akshay . The distribution of closed geodesics

I will give an introduction to the dynamics of higher rank diagonal flows on homogeneous spaces,

including both the rigidity theorems of such flows and their applications to orbits of arithmetic interest,

in particular CM points and integer points on spheres.

I hope to cover parts of the following papers:

Einsiedler, Manfred ; Lindenstrauss, Elon ; Michel, Philippe ; Venkatesh, Akshay . The distribution of closed geodesics

2019
Nov
24

Repeats every week every Sunday until Sat Feb 01 2020 .

2:00pm to 4:00pmRoss 70

Tentative syllabus

1. Mathematical models of classical and quantum mechanics.

2. Correspondence principle and quantization.

3. Classical and quantum computation: gates, circuits, algorithms

(Shor, Grover). Solovay-Kitaev. Some ideas of cryptography

4. Quantum noise and measurement, and rigidity of the Poisson bracket.

5. Noisy classical and quantum computing and error correction, threshold theorem- quantum fault tolerance (small noise is good for quantum computation). Kitaev's surface code.

2020
Jan
08

2020
Jan
22

2019
Dec
18

12:00pm to 1:00pm

Ross 70

Title: Extending the Spectral Radius to Finite-Dimensional Power-Associative Algebras

Abstract: The purpose of this talk is to introduce a new concept, the \textit{radius} of elements in arbitrary finite-dimensional power-associative algebras over the field of real or complex numbers. It is an extension of the well known notion of the spectral radius.

As examples, we shall discuss this new radius in the setting of matrix algebras, where it indeed reduces to the spectral radius, and then in the Cayley-Dickson algebras, where it is something quite different.

2019
Dec
12

2019
Oct
31

2:30pm to 3:30pm

Manchester Building (Hall 2), Hebrew University Jerusalem

Title: Quantum footprints of symplectic rigidity

Abstract: I'll discuss an interaction between symplectic topology, a rapidly developing mathematical area originated as a geometric language for problems of classical mechanics, and quantum mechanics. On one hand, ideas from quantum mechanics give rise to new structures on the symplectic side, and quantum mechanical insights lead to useful symplectic predictions. On the other hand, some phenomena discovered within symplectic topology admit a translation into the language of quantum mechanics.

Abstract: I'll discuss an interaction between symplectic topology, a rapidly developing mathematical area originated as a geometric language for problems of classical mechanics, and quantum mechanics. On one hand, ideas from quantum mechanics give rise to new structures on the symplectic side, and quantum mechanical insights lead to useful symplectic predictions. On the other hand, some phenomena discovered within symplectic topology admit a translation into the language of quantum mechanics.

2019
Nov
13

12:00pm to 1:00pm

Ross 70

Title: The Wiener spectrum and Taylor series with pseudo-random coefficients.

Abstract:

Abstract: