February 2009 - ITP-quantumseminare

talk next week
by Roger Colbeck 20 Feb '09

20 Feb '09

Hi all, Next Tuesday's talk will be in HIT K52 at 5pm. It will be by Oscar (see below for details). Cheers, Roger Title: Using information to extract work - beyond thermodynamics. Abstract: I am going to talk about a paper that has just been finished and is not yet on the arxiv. The paper deals with the relation between information and thermodynamic work. If one has a system with energy it is necessary to have some information about the system in order to extract useful work. We show how to use information to extract work in a concrete setting, and derive expressions for how much work one can extract given ones information. These derivations are done in the smooth entropy paradigm, and are therefore valid for finite numbers of particles. We conclude that ideas from information theory can be used to extend thermodynamics to the nano-scale.

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Movie
by Forster Manuel 16 Feb '09

16 Feb '09

Hi all, Tomorrow after Dejans talk there will be the possibility to watch a good movie at IFW E 44, from 18:30 to approx. 21:00. For dinner we can get something near IFW or call a delivery service. Any suggestions for the movie to watch are welcome. Best regards. Manuel

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[QI] QI Seminar
by Dejan D. Dukaric 16 Feb '09

16 Feb '09

Dear All, This weeks research day on Tuesday will be at the Computer Science Building. I will present a recent paper by Horodecki et al. (see arXiv: 0902.0912). Speaker: Dejan Dukaric Title: Quantum Mutual Independence Time: 5 pm Place: IFW D44 Abstract: We introduce the concept of mutual independence -- correlations shared between distant parties which are independent of the environment. This notion is more general than the standard idea of a secret key -- it is a fully quantum and more general form of privacy. The states which possess mutual independence also generalize the so called private states -- those that possess private key. We then show that the problem of distributed compression of quantum information at distant sources can be solved in terms of mutual independence, if free entanglement between the senders and the receiver is available. Namely, we obtain a formula for the sum of rates of qubits needed to transmit a distributed state between Alice and Bob to a decoder Charlie. We also show that mutual independence is bounded from above by the relative entropy modulo a conjecture, saying that if after removal of a single qubit the state becomes product, its initial entanglement is bounded by 1. We suspect that mutual independence is a highly singular quantity, i.e. that it is positive only on a set of measure zero; furthermore, we believe that its presence is seen on the single copy level. This appears to be born out in the classical case. Cheers, Dejan

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Visit and Talk of Sara Felloni
by Stefan Wolf 11 Feb '09

11 Feb '09

Good afternoon, It is my pleasure to announce that we will have a visitor this Thursday evening and Friday. It is Sara FELLONI from Milano. On Friday, she will present her Ph.D. work entitled: "Decoherence, Errors and Noise Effects in Quantum Information Processing". The talk is scheduled for 14:00 in IFW E44. Sara will arrive on Thursday evening, and I suggest we could go for dinner with her somewhere in town. I hope many of you will join. Stefan

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Talk next week (note day)
by Roger Colbeck 06 Feb '09

06 Feb '09

Hi all, Next week's talk will be on Thursday at 4pm in HIT K52 by Fabio Pedrocchi on his master's thesis, "A de Finetti representation theorem for infinite-dimensional quantum systems: tests of robustness." The abstract is attached. See you there, Roger

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talk next Tuesday
by Roger Colbeck 01 Feb '09

01 Feb '09

Hi all, Next Tuesday's talk will be at 5pm in HIT K51 by Philippe Labouchere on his master's thesis. The title is Coherent One-Way protocol: study of possible variants. The abstract is attached. Cheers, Roger

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