Upcoming seminars

Relaxations of Graph Isomorphism

Seminar date and time: 
2015-09-16 15:05
Author: 
David Roberson

We introduce a two player non-local game based on graph isomorphisms. The input for the game is two graphs X and Y, and players attempt to convince a referee that there exists an isomorphism between X and Y. Classically, players can win this game with probability one if and only if a corresponding isomorphism does in fact exist. It is then natural to ask what happens when the players are allowed to make quantum measurements on a shared entangled state, i.e. are permitted to use "quantum strategies".

Logit Dynamics for Local Interaction Games

Seminar date and time: 
2015-09-16 14:30
Author: 
Diodato Ferraioli

The logit choice function is a family of randomized best response functions
parametrised by beta, the inverse noise level, which is used to model
players with limited rationality and knowledge [D. McFadden - Frontiers in
Econometrics, 1974]. We study the behavior of a game when players update
their strategies according to the logit choice function. We focus on two
extremal case: when at each step only one randomly chosen player is allowed
to update and when at each time step players concurrently update.

Location: 
IFAE seminar room

The role of coherences in quantum thermodynamics

Seminar date and time: 
2015-07-23 15:30
Author: 
Giovanni Vacanti

In the context of quantum thermodynamics (QT), it is important to determine which states of a given system have genuine quantum features. In this regard, the concept of asymmetry with respect to time translation can be used to distinguish classical states from quantum states. Loosely speaking, while it might be possible to interprete the thermodynamic properties of states that are symmetric with respect to time translation (i.e.

Location: 
IFAE seminar room

Experimental high-dimensional multipartite entanglement with twisted photons

Seminar date and time: 
2015-07-23 14:30
Author: 
Mehul Malik
Affiliation: 
IQOQI

Initially proposed as a two-particle problem, the concept of entanglement was extended to three particles by Greenberger, Horne, and Zeilinger in 1989. To date, experimental realizations of multipartite states have been limited to two dimensions due to the use of polarization-entangled photons. When the dimensionality of such states is increased, a richer entanglement structure emerges, where the dimensionality of each component particle can be different. The orbital angular momentum (OAM) of photons offers a discrete, high-dimensional Hilbert space for realizing such states.

Location: 
IFAE seminar room
Contact: 
Marcus Huber

Quantum technologies as tools to deepen our understanding of quantum theory and relativity.

Seminar date and time: 
2015-07-20 14:30
Author: 
Ivette Fuentes
Affiliation: 
University of Vienna

Quantum information and quantum metrology can be used to study
gravitational effects such as gravitational waves and the universality of
the equivalence principle. On one hand, the possibility of carrying out
experiments to probe gravity using quantum systems opens an avenue to
deepen our understanding of the overlap of these theories. On the other
hand, incorporating relativity in quantum technologies promises the
development of a new generation of relativistic quantum applications of
relevance in Earth-based and space-based setups. In this talk, I will

Location: 
IFAE Seminar room

Recoverability in quantum information theory (Long talk)

Seminar date and time: 
2015-06-17 14:30 to 16:30
Author: 
Mark Wilde
Affiliation: 
Louisiana State University

The fact that the quantum relative entropy is non-increasing with respect to quantum physical evolutions lies at the core of many optimality theorems in quantum information theory and has applications in other areas of physics. In this work, we establish improvements of this entropy inequality in the form of physically meaningful remainder terms.

The maximum efficiency of nano heat engines depends on more than temperature

Seminar date and time: 
2015-05-22 17:00
Author: 
Mischa Woods

Sadi Carnot's theorem regarding the maximum efficiency of heat engines is considered to be of fundamental importance in the theory of heat engines and thermodynamics. Here, we show that at the nano and quantum scale, this law needs to be revised in the sense that more information about the bath other than its temperature is required to decide whether maximum efficiency can be achieved.

Coherence-assisted single-shot cooling by quantum absorption refrigerators

Seminar date and time: 
2015-05-20 14:30
Author: 
Mark Mitchison

The extension of thermodynamics into the quantum regime has received much attention in recent years. A primary objective of current research is to find thermodynamic tasks which can be enhanced by quantum mechanical effects. With this goal in mind, we explore the finite-time dynamics of absorption refrigerators composed of three qubits. The aim of this finite-time cooling is to reach low temperatures as fast as possible and subsequently extract the cold particle to exploit it for information processing purposes.

Location: 
IFAE seminar room
Contact: 
Marcus Huber

Post-quantum steering

Seminar date and time: 
2015-05-19 14:30
Author: 
Ana Belen Sainz
Affiliation: 
University of Bristol

The discovery of post-quantum nonlocality, i.e. the existence of nonlocal correlations stronger than any quantum correlations but nevertheless consistent with the no-signaling principle, has deepened our understanding of the foundations quantum theory. In this work, we investigate whether the phenomenon of Einstein-Podolsky-Rosen steering, a different form of quantum nonlocality, can also be generalized beyond quantum theory. While post-quantum steering does not exist in the bipartite case, we prove its existence in the case of three observers.

Location: 
IFAE Seminar room

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