### Quantum Information/Analysis Seminars at the University of South Carolina

Informal seminars that encourage learning, collaboration, and social activities between the participants,
are held weakly. Regular participants include graduate students
and faculty from the Departments of Computer Science and Engineering, Mathematics and Physics.

**Day and Time:** Fridays from 2:15pm to 3:15 pm Eastern Time.

**Place:** LeConte 348.

** Format:** The standard format of the seminar is in-person.

** Alternative Format:**
In the case that the
speaker cannot be with us in person, then the seminar is delivered and attended online via Zoom. In this case, the Zoom link is the following:

Join Zoom Meeting

**Meeting ID:** 818 2090 1820

**Passcode:** 123456

** Date:** 9/8/2023.

** Speaker: ** George Androulakis

** Title: ** The hyperfinite II_1 factor and its use in physics.

** Abstract: **
The hyperfinite II_1 factor is an infinite von Neumann algebra which is very similar to the nxn matrix algebra since it has a finite faithful tracial state. We will describe its construction and indicate some of its uses in physics.

** Seminar notes:**
Blog post

** Date:** 3/31/2023.

** Format: ** Online, via Zoom.

** Speaker: ** Sugata Gangopadhyay

** Affiliation: ** Department of Computer Science and Engineering, Indian Institute of Technology Roorkee.

** Title: ** A quantum algorithm to estimate the Gowers U2 norm and linearity testing of Boolean functions

** Abstract: ** We propose a quantum algorithm to estimate the Gowers U2 norm of a Boolean function, and extend it
into a second algorithm to distinguish between linear Boolean functions and Boolean functions that are
epsilon-far from the set of linear Boolean functions, which seems to perform better than the classical
BLR algorithm.

** Article:** Jothishwaran, C.A., Tkachenko, A., Gangopadhyay, S. et al. A quantum algorithm to estimate the Gowers U2
norm and linearity testing of Boolean functions. Quantum Inf Process 19, 311 (2020).

** Date:** 3/3/2023.

** Speaker: ** George Androulakis

** Title: ** Petz-Renyi divergence between Gaussian states.

** Abstract: **
In the classical information theory, the Renyi divergence is an extension of the Kullback-Leibler divergence. Indeed, when the parameter of the Renyi divergence approaches 1, then the Renyi divergence approaches the Kullback-Leibler divergence.
Similarly, in quantum information theory, the Petz-Renyi divergence is an extension of the Umegaki relative entropy, i.e. when the parameter of the Petz-Renyi divergence approaches 1, then the Petz-Renyi divergence approaches the Umegaki relative entropy. Given two quantum states, it is an interesting problem to determine the values of the parameter of the Petz-Renyi divergence for which the Petz-Renyi divergence is finite. I will present a recent work with Tiju Cherian John where we solve this problem for a large class of Gaussian states. In particular, we verify a conjecture of Seshadreeshan, Lami and Wilde in some cases.

** Seminar notes:**
Blog post

** Date:** 2/17/2023.

** Speaker: ** George Androulakis

** Title: ** Introduction to Gaussian states.

** Abstract: **
The Gaussian states form a non-commutative analogue of the normal distribution. They are used in continuous variables quantum information in order to model quantum interactions of photons. In this introductory talk I will present their main definitions and examples.

** Seminar notes:**
Blog post

** Date:** 2/3/2023.

** Speaker: ** George Androulakis

** Title: ** Relative entropy via distribution of observables

** Abstract: **
The Umegaki relative entropy is an important tool in quantum information. The distribution of an observable with respect to a state is an important tool in quantum probability. We show how the first can be described via the second. The talk is based on joint work with Tiju Cherian John and can be found in https://arxiv.org/abs/2203.01964

** Seminar notes:**
Blog post.

** Date:** 1/27/2023.

** Speaker: ** George Androulakis

** Title: ** Classical and Quantum Divergences

** Abstract: **
We will overview classical and quantum divergences, and we will give a method for computing quantum divergences based on their classical counterparts. The talk will be based on joint work with Tiju Cherian John and can be found in https://arxiv.org/abs/2203.01964

** Seminar notes:**
Blog post.

** Dates:** 11/18 and 12/2 in 2022.

** Speaker: ** Tiju Cherian John

** Title: ** Violation of Bell's Inequality: A Quantum Probabilistic Take

** Abstract: **
We review the probabilistic underpinning of quantum mechanics as envisioned by John von Neumann and discuss a quantum mechanical example violating Bell's inequality.

** Seminar notes:**
Miro board.

** Dates: ** 10/28, 11/4 and 11/11 in 2022.

** Speaker: ** George Androulakis.

** Title: ** Bell's inequality

** Abstract: **
We will discuss the work of
John Stewart Bell.
Especially we are interested in Bell's 1964 article
On the Einstein Podolsky Rosen paradox.
Aspect, Clauser and Zeilinger played pioneering role in demonstrating a variant of Bell's result
Because of these works, these three researchers were awarded the
Nobel Prize in Physics on October 4th 2022

** Seminar notes:**
Miro board,
Blog post.

**Back to my homepage.****
**