Upcoming seminars

Codes of Maximal Distance and Highly Entangled Subspaces

Seminar date and time: 
2018-12-04 15:00
Author: 
Felix Huber
Affiliation: 
ICFO Barcelona

We present new bounds on the existence of quantum maximum distance separable 
codes (QMDS): the length n of all non-trivial QMDS codes with local dimension 
D and distance d is bounded by n ≤ D^2 + d − 2. We obtain their weight 
distribution by investigating families of QMDS codes, and present additional 
bounds that arise from Rains’ shadow inequalities. Our main result can be seen 
as a generalization of bounds that are known for the two special cases of 
stabilizer QMDS codes and absolutely maximally entangled states, and confirms 

Location: 
GIQ Seminar Room (C5/262)
Contact: 
Felix.Huber@icfo.eu

Emerging 2D Gauge theories in Rydberg atomic systems

Seminar date and time: 
2018-12-04 12:00
Author: 
Alessio Celi
Affiliation: 
IQOQI Innsbruck

Understanding strongly coupled gauge theories is a fundamental challenge of physics, with dramatic

implications both for high energy and condensed matter. Doing it with a quantum simulator is a

formidable test for quantum simulation. Here we show that by exploiting electromagnetic duality, we

can create the Rokhsar-Kivelson Hamiltonian –a 2D U(1) lattice gauge theory that describes quantum

dimers- in running Rydberg experiments by exploiting Rydberg blockade in a novel fashion. Quantum

Location: 
GIQ Seminar Room (C5/262)
Contact: 
alessio.celi@gmail.com

Shannon zero-error capacity from non-local games having no-quantum advantage

Seminar date and time: 
2018-11-14 12:00
Author: 
Dardo Goyeneche
Affiliation: 
Universidad de Antofagasta, Chile

The problem to determine the classical and quantum optimal strategies for quantum games rely at the heart of quantum non-locality and its applications to quantum technologies. These optimal strategies are hard to find even in relatively simple scenarios. In this work, we establish a one-to-one connection existing between the problem of calculating the optimal classical strategy of a game and a well-studied problem in mathematics some decades ago, namely to calculate the excess of a matrix.

Location: 
GIQ Seminar Room (C5/262)
Contact: 
dardomg@gmail.com

Classical Learning Theory

Seminar date and time: 
2018-11-13 14:00
Author: 
Matteo Rosati
Affiliation: 

We will introduce the PAC learning framework for countable function classes. Then we will relax this constraint and consider two general approaches: growth functions and VC dimension (for binary labels).

References: Michael Wolf's notes and references therein.

Location: 
Contact: 

Kitaev honeycomb tensor networks: exact unitary circuits and applications

Seminar date and time: 
2018-10-30 16:00
Author: 
Roman Orus
Affiliation: 
Donostia International Physics Center

The Kitaev honeycomb model is a paradigm of exactly-solvable models, showing non-trivial physical properties such as topological quantum order, abelian and non-abelian anyons, and chirality. Its solution is one of the most beautiful examples of the interplay of different mathematical techniques in condensed matter physics. In this talk I will show how to derive a tensor network (TN) description of the eigenstates of this spin-1/2 model in the thermodynamic limit, and in particular for its ground state.

Location: 
GIQ Seminar Room (C5/262)
Contact: 
mailto:roman.orus@dipc.org

Collective and hydrodynamic behavior in thermal transport.

Seminar date and time: 
2018-10-25 12:00
Author: 
Xavier Alvarez Calafell
Affiliation: 
Universitat Autònoma de Barcelona

Recent experiments using ultrafast laser heating on nanoscale samples have shown significant discrepancies respect to Fourier’s law [1-3]. The reason behind this anomalous behavior is related with the conservation of momentum in phonon-phonon collisions. This conservation law imposes some restrictions on the distribution function of the phonons in a way that these particles cannot move independently and have to move in a coherent form. It will be shown that in this regime a generalized entropy can be defined in terms of the mean energy and the heat flux.

Location: 
GIQ Seminar Room (C5/262)
Contact: 
Xavier.Alvarez@uab.cat

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