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--- seminars [2014/03/28 11:36]
oreshkov
+++ seminars [2018/04/19 12:40]
levonc [Upcoming seminars]
@@ Line 2: / Line 2: @@
 ====== Seminars ======
 Our seminars usually take place in the QuIC seminar room, campus Solbosh, building U, room UA3-219.
 <html>
@@ Line 13: / Line 13: @@
 ===== Upcoming seminars =====
+===== In the past =====
+{| class="seminar"
+|-
+!colspan="2"|A gauge-invariant reversible cellular automata
+|-
+|style="width:55px"|**Speaker:**|| Nathanaël Eon, Université libre de Bruxelles
+|-
+|**Date:** || Wednesday, March 21, 2018, 11:00.
+|-
+|**Abstract:** || Gauge-invariance is a fundamental concept in physics—known to provide the mathematical justification for all four fundamental forces. We created discrete counterparts to the main gauge theoretical concepts, directly in terms of Cellular Automata. More precisely, we describe a step-by-step gauging procedure to enforce local symmetries upon a given Cellular Automaton. We apply it to a simple Reversible Cellular Automaton for concreteness. From a Computer Science perspective, discretized gauge theories may be applied to numerical analysis, quantum simulation, fault-tolerant (quantum) computation. From a mathematical perspective, discreteness provides a simple yet rigorous route straight to the core concepts.
+|}
-===== In the past =====
 {| class="seminar"
 |-
@@ Line 176: / Line 188: @@
 |**Abstract:** || One of the most promising spin-offs of quantum information theory for
 science is the idea of using quantum information processing in order to increase the sensitivity of precision measurements.  The major goal of these "Quantum Enhanced Measurements" (QEM) is to achieve the Heisenberg limit (HL) - a scaling of the sensitivity as 1/N with the number N of quantum resources.  This would represent a major improvement over the standard quantum limit (SQL) in which the sensitivity scales as the inverse square root of N, with a corresponding huge interest for technological applications.
 However, despite about 30 years of efforts, the SQL has been surpassed only by very few experiments so far, and only for small values of N.  Indeed, the standard protocols of QEM require highly entangled states that are typically very prone to decoherence, and are therefore unlikely to scale up to the large numbers of N required before QEM can compete with classical precision measurements.
 \\
 In this talk, I show that by having the N quantum systems interact with a common "quantum-bus", one can achieve Heisenberg limited sensitivity without using or ever creating entanglement.  The quantum bus can be as simple as a single qubit, or as complex as an environment with many degrees of freedom
 over which we have only partial control and which creates therefore decoherence. The scaling with N is robust under local decoherence, and decoherence itself can be used as a signal that allows one to achieve the HL. I will present a general theory of this new kind of measurements, based on the fundamental Quantum Cramer-Rao bound, and illustrate the effect in some detail for the example of the measurement of the length of a cavity using superradiance.
 |}
@@ Line 218: / Line 230: @@
 hope for quite some time that quantum state generation might be a route
 to tackle the Graph Isomorphism problem. We show that for the
 related problem of Index Erasure our method leads to a lower bound
 of Omega(sqrt(N)) which matches an upper bound obtained via reduction
 to quantum search on N elements. This closes an open problem first
 raised by Shi [FOCS'02].
 Our approach is based on two ideas: (i) on the one hand we generalize
 the known additive and multiplicative adversary methods to the case of
 quantum state generation, (ii) on the other hand we show how the
 symmetries of the underlying problem can be leveraged for the design of
 optimal adversary matrices and dramatically simplify the computation of
 adversary bounds. Taken together, these two ideas give the new result
@@ Line 240: / Line 252: @@
 {| class="seminar"
 |-
 !colspan="2"|Entanglement enhancement by photon addition and subtraction:
 a step towards solving the minimum entropy conjecture
 |-
@@ Line 247: / Line 259: @@
 |**Date:** || Thursday, February 17, 2011, 16:00.
 |-
 |**Abstract:** || In view of the recent progress towards on-demand photon addition
 and subtraction (see [1]), we have systematically studied how these
 operations, despite being local, can enhance the entanglement present in a two-mode
 vacuum squeezed state, which a the state customarily used in quantum protocols
 involving light. I will also explain our efforts towards a proof of the so-called
 “minimum entropy conjecture”, which states that the capacity of Gaussian single-mode
 communication channels such as lossy fibers or amplifiers is attained by using
 input coherent states [2]. I will show how this latter problem is related to the former one,
 and can be analytically addressed by exploiting the concept of majorization.
 \\
 [1] A. Zavatta, V. Parigi, M. S. Kim, H. Jeong, and M. Bellini; Phys. Rev.
 Lett. 103, 140406 (2009).
 \\
 [2] V. Giovannetti, S. Guha, S. Lloyd, L. Maccone, and J. H. Shapiro; Phys.
 Rev. A 70, 032315 (2004).
@@ Line 273: / Line 285: @@
 |**Date:** || Wednesday, April 28, 2010, 12:00.
 |-
 |**Abstract:** || Quantum particles have the ability to be very closely
 correlated, a phenomenon called entanglement. I will first explain
 how its presence can assist in performing computational tasks. For
 instance, a calculator with limited logical operations is boosted
 beyond its own capabilities to a full power computer when given
 access to quantum correlated particles. Moreover, with the help
 of quantum correlations a single quantum particle can be used as an
 external control to evolve and measure any quantum system remotely.
  \\
 While these are man made, externally controlled applications of
 quantum correlations one can wonder if existing natural processes
 exploit their power. Indeed quantum fields and other many-body
 models support entanglement at a macroscopic scale below a specific
 transition temperature. The role of the entanglement here is to
 help “squeeze” the energy below the classical level, by forcing
 collective behaviour. This links the presence of entanglement in
 natural systems to the occurrence of Bose-Einstein condensation
 and quantum phase transitions.
 |}
@@ Line 303: / Line 315: @@
 |**Abstract:** || We propose a new physical approach for encoding and processing of quantum
 information in ensembles of multilevel quantum systems, where the
 different bits are not carried by individual particles but associated with
 the collective population of different internal levels. One- and two-bit
 gates are implemented by collective internal state transitions taking
 place in the presence of an excitation blockade mechanism, which restricts
@@ Line 351: / Line 363: @@
 {| class="seminar"
 |-
 !colspan="2"|Block entropy analysis by lumping: Measuring the uncomputable
 |-
 |style="width:55px"|**Speaker:**|| Kostas Karamanos, University of Athens, Greece.
@@ Line 362: / Line 374: @@
 {| class="seminar"
 |-
 !colspan="2"|A pictorial approach to measurement-based quantum computing
 |-
 |style="width:55px"|**Speaker:**|| Ross Duncan, University of Oxford, UK.
@@ Line 373: / Line 385: @@
 {| class="seminar"
 |-
 !colspan="2"|Methods for estimating transmission characteristics of Gaussian quantum channels with memory
 |-
 |style="width:55px"|**Speaker:**|| Oleg Pilyavets, P. N. Lebedev Physical Institute, Moscow, Russia.
@@ Line 381: / Line 393: @@
 |**Abstract:** || Methods for analytical and numerical estimation of classical capacity for lossy bosonic Gaussian channel with memory are proposed. The methods above are also demonstrated to be useful for calculating of achievable rates. New phenomena namely, violations of quadrature and mode symmetries for classical capacity are explained. The role of channel memory is analyzed. Relation between quantum channels problems and quantum tomography (probability representation) is discussed for continuous variable and spin systems.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Proof of principle of a new algorithm for factoring arbitrary numbers with a single recorded interferogram
 |-
 |style="width:55px"|**Speaker:**|| Vincenzo Tamma, University of Maryland, Baltimore, USA.
@@ Line 395: / Line 407: @@
 {| class="seminar"
 |-
 !colspan="2"|Dissipation in Laplacian fields across irregular boundaries
 |-
 |style="width:55px"|**Speaker:**|| Kostas Karamanos, University of Athens, Greece.
@@ Line 406: / Line 418: @@
 {| class="seminar"
 |-
 !colspan="2"|Positive Wigner functions and uncertainty relation in the space of mixed states
 |-
 |style="width:55px"|**Speaker:**|| Aikaterini Mandilara, QuIC.
@@ Line 417: / Line 429: @@
 {| class="seminar"
 |-
 !colspan="2"|Repeatable quantum memory channels
 |-
 |style="width:55px"|**Speaker:**|| Tomas Rybar, Research Center for Quantum Information, Slovak Academy of Sciences, Slovakia.
@@ Line 428: / Line 440: @@
 {| class="seminar"
 |-
 !colspan="2"|On continuous variable quantum algorithms for oracle identification problems
 |-
 |style="width:55px"|**Speaker:**|| Barry Sanders, iCORE Chair of Quantum Information Science, University of Calgary, Canada.
@@ Line 434: / Line 446: @@
 |**Date:** || Tuesday, June 9, 2009, 15:00.
 |-
 |**Abstract:** || We establish a framework for oracle identification problems in the
 continuous variable setting, where the stated problem necessarily is the same as in the discrete variable case. Continuous variables are
 manifested through a continuous representation in an infinite-dimensional
 Hilbert space. We apply this formalism to the Deutsch-Jozsa problem and show that, due to an uncertainty relation between
 the continuous representation and its Fourier-transform dual representation, the corresponding Deutsch-Jozsa algorithm is
 probabilistic hence forbids an exponential speed-up.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Capacity of a Bosonic channel with Gauss-Markov memory
 |-
 |style="width:55px"|**Speaker:**|| Joachim Schäfer, QuIC.
@@ Line 453: / Line 465: @@
 of a classical and a quantum channel with such a memory: the Gaussian additive-noise channel and a bosonic Gaussian noise
 channel. For both cases, we show that the capacity is found by a so-called "water filling" solution, and present explicit results
 in certain input power regions. Finally, we show that the results for the quantum channel translate in the classical limit
 to the results for its classical counterpart.
 |}
@@ Line 459: / Line 471: @@
 {| class="seminar"
 |-
 !colspan="2"|Coherent-state quantum key distribution with multiletter alphabets
 |-
 |style="width:55px"|**Speaker:**|| Denis Sych, Max Planck Institute for the Science of Light, Erlangen, Germany.
@@ Line 468: / Line 480: @@
 {| class="seminar"
 |-
 !colspan="2"|On Symmetric Informationally-Complete Positive-Operator Valued Measures (SIC POVMs)
 |-
 |style="width:55px"|**Speaker:**|| Thomas Durt, TONA, VUB.
@@ Line 474: / Line 486: @@
 |**Date:** || Friday, June 27, 2008, 12:00.
 |-
 |**Abstract:** || SIC POVMs present interesting applications in Quantum Tomography.
 Covariant SIC POVMs under the Heisenberg-Weyl group are of particular interest and have been the object of intensive
 research. They seemingly exist for all finite dimensions, although most often their existence was merely established by numerical methods. Moreover they satisfy a property that was conjectured by
@@ Line 483: / Line 495: @@
 {| class="seminar"
 |-
 !colspan="2"|Thick Quantum Hologram
 |-
 |style="width:55px"|**Speaker:**|| Denis Vasilyev, V. A. Fock Physics Institute, St.-Petersburg, Russia.
@@ Line 492: / Line 504: @@
 {| class="seminar"
 |-
 !colspan="2"|Quantum compatible information as an effective tool for physical problems
 |-
 |style="width:55px"|**Speaker:**|| Denis Sych, Max-Planck Research Group,
@@ Line 507: / Line 519: @@
 properties of bipartite quantum states, calculation of quantum
 information exchange between dipole-dipole interacting atoms or
 molecules, improving of quantum key distribution protocols, etc.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Quantum gates by adiabatic passage
 |-
 |style="width:55px"|**Speaker:**|| Xavier Lacour, Université de Bourgogne, Dijon, France.
@@ Line 523: / Line 535: @@
 {| class="seminar"
 |-
 !colspan="2"|Phase space methods for discrete quantum systems
 |-
 |style="width:55px"|**Speaker:**|| David Gross, Imperial College, UK.
@@ Line 541: / Line 553: @@
 functions or potential shortcomings of the analogy for mixed states.
 |}
 {| class="seminar"
 |-
 !colspan="2"|On quantum de Finetti theorems
 |-
 |style="width:55px"|**Speaker:**|| Robert Koenig, CQC, University of Cambridge, UK.
@@ Line 571: / Line 583: @@
 |**Date:** || Friday, January 19, 2007, 11:00.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Search via quantum walk
 |-
 |style="width:55px"|**Speaker:**|| Jérémie Roland, QuIC.
@@ Line 597: / Line 609: @@
 {| class="seminar"
 |-
 !colspan="2"|Casimir-Polder intermolecular forces
 |-
 |style="width:55px"|**Speaker:**|| Roberto Passante, University of Palermo, Italy.
@@ Line 603: / Line 615: @@
 |**Date:** || Friday, June 16, 2006, 9:00.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Hyper-entangled two-photon states for quantum communication applications
 |-
 |style="width:55px"|**Speaker:**|| Marco Barbieri, Quantum Optics Group,
 Department of Physics, University of Roma "La Sapienza", Italy.
 |-
@@ Line 619: / Line 631: @@
 {| class="seminar"
 |-
 !colspan="2"|Quantum realizability criteria for joint probabilities
 |-
 |style="width:55px"|**Speaker:**|| Stefano Pironio, ICFO, Barcelona, Spain.
@@ Line 631: / Line 643: @@
 point in the hierarchy. Our approach can be used to obtain upper-bounds on the quantum violation of arbitrary Bell inequalities. It yields, for
 instance, tight bounds for the violation of the Collins et al inequalities.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Local equivalence of stabilizer states
 |-
 |style="width:55px"|**Speaker:**|| Maarten Van den Nest, ESAT, KULeuven.
@@ Line 644: / Line 656: @@
 quantum error-correction and measurement-based quantum computation. It is well known that stabilizer states have a high degree of genuine
 multi-party entanglement, and that this entanglement is one of the key
 ingredients responsible for the success with which stabilizer states
 are used in their applications. Therefore, a detailed study of the multipartite entanglement properties of stabilizer states is called for.
 When considering the entanglement properties of stabilizer states,
 a natural subject is a study of the action of local operations on
 stabilizer states and a classification of stabilizer states under local
@@ Line 659: / Line 671: @@
 a proof that the notions of SLOCC equivalence, local unitary equivalence
 and local Clifford equivalence all coincide for stabilizer states,
 showing that there is in fact only one type of local equivalence
 of stabilizer states. The proof that local unitary equivalence of
 stabilizer states coincides with  local Clifford equivalence (joint work
@@ Line 668: / Line 680: @@
 {| class="seminar"
 |-
 !colspan="2"|Adiabatic passage for quantum information
 |-
 |style="width:55px"|**Speaker:**|| Stephane Guerin, Laboratoire de Physique,  Université de Bourgogne, Dijon, France.
@@ Line 675: / Line 687: @@
 |-
 |**Abstract:** || Adiabatic passage techniques for the control of atomic and molecular
 processes by laser and cavity fields will be presented. I will then
 discuss applications to quantum information processes such as
 the generation of photon number states on demand,
 entangled states and quantum gates in a cavity.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Nonsignalling correlations and Quantum Mechanics
 |-
 |style="width:55px"|**Speaker:**|| Nick Jones, QUIC and University of Bristol, UK
@@ Line 701: / Line 713: @@
 {| class="seminar"
 |-
 !colspan="2"|Simuler un POVM à l'aide de boîtes non locales et de communication classique
 |-
 |style="width:55px"|**Speaker:**|| Julien Degorre, Laboratoire de Recherche en Informatique (LRI), Orsay, France
@@ Line 707: / Line 719: @@
 |**Date:** || Friday, April 22, 2005, 14:30.
 |-
 |**Abstract:** || Une paire de boîtes non locales est un gadget qui prend deux bits
 (x et y) en entrée et qui produit deux bits (a et b) en sortie,
 de telle sorte que la parité de a et b est toujours égale
 à la conjonction de x et y. La magie, bien sûr, vient du fait
 qu'une des boîtes produit a à partir de x seulement alors que
 l'autre produit b à partir de y, et que ces deux boîtes ne
 communiquent pas! Impossible, direz-vous? Eh bien vous avez raison
 même si les boîtes partagent une quantité
 illimitée d'intrication!
@@ Line 719: / Line 731: @@
 faible que la communication d'un bit classique. On sait pourtant que
 toute paire de mesures projectives (von Neumann) sur une paire EPR
 partagée peut être simulée par une seule utilisation
 d'une paire de boîtes non locales (Cerf-Gisin-Massar-Popescu-04).
 Qu'en est-il de la simulation d'une paire de POVM sur un paire EPR
 partagée? (Simulation qu'on sait déjà; faire par la
 transmission espérée de 6 bits classique (Methot-03).)
 Je présenterai un résultat, qui répond à
 cette question si on permet également un peu de communication
 classique. Aprés avoir introduit les boîtes non locales,
 je présenterai un protocole qui permet de simuler
@@ Line 733: / Line 745: @@
 et pourrait donner une nouvelle intuition sur le probléme.
 Le compromis à faire entre le nombre d'utilisations de boîtes non
 locales et le nombre de bits de communication sera discuté,
 ainsi que le rôle de chacune de ces ressources.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Key distillation from Gaussian states by Gaussian operations
 |-
 |style="width:55px"|**Speaker:**|| Miguel Navascués, ICFO, Barcelona, Spain
@@ Line 745: / Line 757: @@
 |**Date:** || Friday, January 21, 2005, 10:00.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Macroscopic Phenomena of Quantum Entanglement.
 |-
 |style="width:55px"|**Speaker:**|| Caslav Brukner, University of Vienna, Austria
@@ Line 757: / Line 769: @@
 entanglement exits in macroscopic samples of Cooper Nitrate at temperatures below 5 Kelvin.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Lossless quantum compression.
 |-
 |style="width:55px"|**Speaker:**|| Caroline Rogers, University of Warwick, UK
@@ Line 789: / Line 801: @@
 of these open questions.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Extremal covariant maps and optimal cloning of a couple of mutually unbiased bases
 |-
 |style="width:55px"|**Speaker:**|| Giulio Chiribella, University of Pavia, Italy
@@ Line 803: / Line 815: @@
 {| class="seminar"
 |-
 !colspan="2"|A general solution to the Mean King's problem in prime power dimensions, Bell states and mutually unbiased bases
 |-
 |style="width:55px"|**Speaker:**|| Thomas Durt, TONA, VUB
@@ Line 817: / Line 829: @@
 Heisenberg-Weyl group (sometimes called Pauli group), contains //N2</sup>// elements
 which are in one to one correspondence with (so-called) Bell states;
 it is generated by discrete realisations of spatial translations
 and Galilean boosts. When the dimension N is a prime power //p<sup>m</sup>//, there exists a finite field of N elements. We derive a new way to express the mutually unbiased bases in terms of the (operations of the) associated finite field of N elements.  We also derive the transformation law for the Bell states when a basis transforms into a mutually unbiased basis. In prime dimensions, this reduces to a well-known property of the Jacobi or Clifford group.
 All this leads to a new solution to the Mean King's problem in arbitrary prime power dimensions, that is, it provides a way to ascertain the values of N+1 observables that are maximally complementary in the sense that they are diagonal in mutually unbiased bases.
 |}
 {| class="seminar"
 |-
 !colspan="2"|The Second Law and the Holevo Bound
 |-
 |style="width:55px"|**Speaker:**|| Koji Maruyama, QUIC
@@ Line 841: / Line 853: @@
 allow more information storage, it could still be under the umbrella of
 thermodynamics.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Entanglement, Critical Phenomena, and RG Flows
 |-
 |style="width:55px"|**Speaker:**|| Enrique Rico Ortega, University of Barcelona
@@ Line 862: / Line 874: @@
 {| class="seminar"
 |-
 !colspan="2"|Zeno effect and non-decaying subspaces in unstable quantum systems
 |-
 |style="width:55px"|**Speaker:**|| Evgueni Karpov, Instituts Internationaux de Physique et de Chimie Solvay
@@ Line 883: / Line 895: @@
 conditions.
 |}
 {| class="seminar"
 |-
@@ Line 904: / Line 916: @@
 length a_s and temperature T.
 |}
 {| class="seminar"
 |-
@@ Line 924: / Line 936: @@
 remarks.
 |}
 {| class="seminar"
 |-
@@ Line 946: / Line 958: @@
 any p and tensor products of single mode channels.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Quantum correlations: knowledge excesses and Bell inequalities
 |-
 |style="width:55px"|**Speaker:**|| Radim Filip, Palacky University, Olomouc, Czech Republic
@@ Line 966: / Line 978: @@
 down-conversion.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Programmable quantum multimeters and their optical implementations
 |-
 |style="width:55px"|**Speaker:**|| Miloslav Dusek, Palacky University, Olomouc, Czech Republic
@@ Line 988: / Line 1000: @@
 devices are proposed and experimental results are presented.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Thermodynamical Detection of Entanglement by Maxwell's Demons
 (and some demonic implications)
 |-
 |style="width:55px"|**Speaker:**|| Koji Maruyama, Imperial College, UK
@@ Line 998: / Line 1010: @@
 |**Date:** || Monday, April 19, 2004, 12:30.
 |-
 |**Abstract:** || Entangled states are said to be more correlated than classically correlated
 states. Besides tasks in information processing, can we make use of this
 excess correlation in entanglement to do something physically useful?
 Generalising classical Szilard's engine, we show we can devise a
 thermodynamical process that reveals the usefulness of entanglement. The
 idea leads to the "thermodynamical separability criterion", which can be seen
 as a kind of entanglement witness with locally observable quantities.
 We will also give an analysis on whether we can derive results in quantum
 information theory by taking an axiomatic approach from the Second Law of
 thermodynamics, combining with the above process.
 |}
 {| class="seminar"
 |-
@@ Line 1033: / Line 1045: @@
 attacks exists.
 |}
 {| class="seminar"
 |-
@@ Line 1053: / Line 1065: @@
 of 10^3 W.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Kinetic Theory of a Bose Condensed Gas
 |-
 |style="width:55px"|**Speaker:**|| Patrick Navez, QUIC
@@ Line 1067: / Line 1079: @@
 {| class="seminar"
 |-
 !colspan="2"|Two aspects of non-locality: classical production cost and extremal no-signalling correlations.
 |-
 |style="width:55px"|**Speaker:**|| Stefano Pironio, QUIC
@@ Line 1078: / Line 1090: @@
 {| class="seminar"
 |-
 !colspan="2"|An experimental implementation of quantum coin tossing
 |-
 |style="width:55px"|**Speaker:**|| Louis-Philippe Lamoureux, QUIC
@@ Line 1084: / Line 1096: @@
 |**Date:** || Thursday, December 11, 2003, 12:00
 |}
 {| class="seminar"
 |-
 !colspan="2"|Interaction, entanglement, and the classical limit
 |-
 |style="width:55px"|**Speaker:**|| Thomas Durt, TONA, Vrije Universiteit Brussel
@@ Line 1095: / Line 1107: @@
 |**Abstract:** || We briefly define quantum entanglement and present a troubling property associated with it: non-locality. We show that two interacting systems that are initially non-entangled remain so during the interaction provided that the Hamiltonian does not couple them to bi-orthogonal states. Then, we prove that non-entangling Hamiltonians (for all non-entangled states) are de facto separable; in other words, there is no interaction without entanglement. Finally, we show that, in simple cases, the non-entangling regime corresponds to our classical conceptions about what physicists call particles. This confirms the predictability sieve criterion of Zurek, defined in the framework of the decoherence approach, according to which classical islands correspond to the regions of the Hilbert space where the (quantum) information of the reduced system is maximal.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Special QUIC seminar
 |-
 |style="width:55px"|**Speaker:**|| Thomas Durt, TONA, Vrije Universiteit Brussel
@@ Line 1104: / Line 1116: @@
 |**Date:** || Wednesday, October 8, 2003, 12:00
 |-
 |**Abstract:** || For this special QUIC seminar, Thomas Durt will comment the video tape of a program on classical (but also quantum!) cryptography that was broadcast by the Vlaamse Television (Canvas, VRT) in the beginning of 2003. This program (called "Over Leven") stars people from the VUB (including Thomas Durt) and also made a few shots in the ULB optics lab where quantum information experiments are being carried out.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Statistical algorithmic compressibility analysis of DNA sequences. Towards algorithmic laws for Biology?
 |-
 |style="width:55px"|**Speaker:**|| Kostas Karamanos, CENOLI, ULB
@@ Line 1115: / Line 1127: @@
 |**Date:** || Monday, September 22, 2003, 12:00
 |}
 {| class="seminar"
 |-
 !colspan="2"|On the existence of mutually unbiased bases in arbitrary dimensions
 |-
 |style="width:55px"|**Speaker:**|| Claude Archer, Service de Mathématique,
@@ Line 1125: / Line 1137: @@
 |**Date:** || Friday, September 12, 2003, 12:00
 |}
 {| class="seminar"
 |-
 !colspan="2"|Entanglement and spin squeezing in a quantum phase transition
 |-
 |style="width:55px"|**Speaker:**|| Guillaume Palacios, Groupe de Physique
@@ Line 1135: / Line 1147: @@
 |**Date:** || Wednesday, August 20, 2003, 3 pm
 |}
 {| class="seminar"
 |-
 !colspan="2"|Cloning the Entanglement of Quantum States
 |-
 |style="width:55px"|**Speaker:**|| Louis-Philippe Lamoureux, QUIC
@@ Line 1144: / Line 1156: @@
 |**Date:** || Wednesday, June 18, 2003, 12:00
 |}
 {| class="seminar"
 |-
 !colspan="2"|Non-Gaussian Cloning of Gaussian States
 |-
 |style="width:55px"|**Speaker:**|| Patrick Navez, QUIC
@@ Line 1153: / Line 1165: @@
 |**Date:** || Wednesday, June 11, 2003, 12:00
 |}
 {| class="seminar"
 |-
 !colspan="2"|Quantum coin tossing in the presence of noise
 |-
 |style="width:55px"|**Speaker:**|| Jonathan Barrett, QUIC
@@ Line 1167: / Line 1179: @@
 {| class="seminar"
 |-
 !colspan="2"|Construction of a Shared Secret Key Using Continuous Variables
 |-
 |style="width:55px"|**Speaker:**|| Jean Cardinal (Computer Science Departement, ULB) and Gilles Van Assche (QUIC)
@@ Line 1175: / Line 1187: @@
 |**Abstract:** || Motivated by recent advances in quantum cryptography with continuous variables, we study the problem of extracting a shared digital secret key from two correlated real values. Alice has access to a real value //X<sub>A</sub>//, and Bob to another value //X<sub>B</sub>// such that //I(X<sub>A</sub>; X<sub>B</sub>)>0//. They wish to convert their values into a shared secret digital information while leaking as little information as possible to Eve. We show how the problem can be decomposed in two subproblems known in other contexts. The first is the design of a quantizer that maximizes a mutual information criterion, the second is known as coding with side information.
 |}
 {| class="seminar"
 |-
 !colspan="2"|An Introduction to Godel's Incompleteness Theorem
 |-
 |style="width:55px"|**Speaker:**|| Bruno Marchal, IRIDIA, ULB
@@ Line 1186: / Line 1198: @@
 |**Abstract:** || We propose a relatively simple proof of Godel's incompleteness theorem. The proof will give some conceptual motivation for the Church Turing Thesis, and provide clues on why universal computer are "really" universal. We will end up with suggestions about a possible application on Universal Quantum Computing.
 |}
 {| class="seminar"
 |-
 !colspan="2"|Quantum game theory
 |-
 |style="width:55px"|**Speaker:**|| Jiangfeng Du, University of Science and Technology of China, Hefei, P.R. China
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 |**Abstract:** || Game theory is a theory of decision making, which provides powerful tools for investigating situations in which several parties make desisions according to their personal interest. I will give an account of how the parties would decide in a situation which involves contest, rivalry, or struggle. Such game-theory problems have been found to be relevant to social science, biology, or economics. Game theory was born in 1944 with the publication of the book "Theory of Games and Economic Behavior" by J. Von Neumann and O. Morgenstern. Recently, game theory was extended to the quantum world, and quantum strategies were discussed and shown to be powerful. In this talk, I will focus on the Prisoner's Dillema, a famous example in classical game theory, and I will introduce some recent results on quantum games.
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 !colspan="2"|Bell inequalities for arbitrarily high dimensional systems
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 |style="width:55px"|**Speaker:**|| Serge Massar, QUIC
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 |**Abstract:** || We develop a novel approach to Bell inequalities based on a constraint that the correlations exhibited by local realistic theories must satisfy. This is used to construct a family of Bell inequalities for bipartite quantum systems of arbitrarily high dimensionality which are strongly resistant to noise. In particular our work gives an analytic description of numerical results of D. Kaszlikowski, P. Gnacinski, M. Zukowski, W. Miklaszewski, A. Zeilinger, Phys. Rev. Lett. 85, 4418 (2000) and T. Durt, D. Kaszlikowski, M.  Zukowski, quant-ph/0101084, and generalizes them to arbitrarily high dimensionality.
 |}
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 !colspan="2"|A "mechanist" approach to the foundations of quantum mechanics
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 |style="width:55px"|**Speaker:**|| Bruno Marchal, IRIDIA, ULB
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 !colspan="2"|Some interesting properties of quTrits in relation with non-locality and quantum cryptography
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 |style="width:55px"|**Speaker:**|| Thomas Durt, TONA, Vrije Universiteit Brussel
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 !colspan="2"|Linear Optics Quantum Computation
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 |style="width:55px"|**Speaker:**|| Sara Schneider, QUIC
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 !colspan="2"|Optical information storage in an atomic medium
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 |style="width:55px"|**Speaker:**|| Sofyan Iblisdir, QUIC
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 !colspan="2"|Overview of Security Proofs for Quantum Key Distribution
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 |style="width:55px"|**Speaker:**|| Gilles Van Assche, QUIC
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 |**Date:** || Wednesday, March 14, 2001, 4 pm
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 !colspan="2"|On the reversible extraction of classical information from a quantum source
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 |style="width:55px"|**Speaker:**|| Andreas Winter, Universitaet Bielefeld, Germany
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 !colspan="2"|Some new results on quantum entanglement
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 |style="width:55px"|**Speaker:**|| Frank Verstraete and Koenraad Audenaert, K. U. Leuven
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 !colspan="2"|Simulations and measurements in ion trap quantum computers
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 |style="width:55px"|**Speaker:**|| Sara Schneider, QUIC
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 |**Abstract:** || Quantum computers are, in a way, measurement devices which allow to perform and also simulate experiements. I will first give a short introduction into ion trap quantum computation. Then I will discuss how to use an ion trap quantum computer to simulate a 'trit' with two qubits and, as an application of this, propose a measurement of an SU(3) geometrical phase in ion traps. The last part will be concerned with the simulation of large angular momentum systems in ion traps. The focus will be on the Dicke-model, a model which includes coherent driving and collective decoherence of a set of two-level systems. I will discuss the semiclassical dynamics of the system and show for the case of two qubits how entanglement arises.
 |}
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 !colspan="2"|Quantum and/or classical secret sharing
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 |style="width:55px"|**Speaker:**|| Gilles Van Assche, QUIC
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 |**Date:** || Wednesday, September 20, 2000, 2:30 pm
 |}