National University of Singapore

Post-Doc, Center for Quantum Technologies

About

I am (was?) a computer scientist (theoretical physicist?) who is interested in fundamental questions about quantum physics, in the field of quantum computing and quantum information theory.

Currently, I am a Research Fellow at the Centre of Quantum technologies, CQT,  National University of Singapore in the group of Andreas Winter.
Previous position

2010 -... Research Fellow  at Interdisciplinary Theory Group Centre for Quantum Technologies, National University of Singapore, Singapore.

10/09-12/09 Research Fellow at the School of Informatics, the University of Edinburgh, UK.

2008 -2009 Research Fellowl, part of the European QICS EC-FP6-STREP grant. Équipe calcul quantique, CAPP, Laboratoire d’Informatique de Grenoble, France.
PhD Thesis

I defended my thesis, entitled Quantifying non-locality, in September 2007. The thesis covers non-locality (not just quantum non-locality) in terms of communication complexity.
Formation

    PhD in Computer Science, in superposition between two groups:

University of Paris Sud at Orsay, with Miklos Santha in the Quantum Computation Group at LRI and
University of Montréal, with Gilles Brassard in the Laboratoire Informatique Theorique Quantique.

    Masters degree in Mathematical Physics, University Luminy (Centre of Theoritical Physics in Marseille)

    Masters theses topics:
        Quantum decoherence, with Giles Brassard at the Laboratoire Informatique Theorique and Quantique, in Montreal (first year);
        and Decoherence in Josephson junctions, with Franck Hekkings at the Theoritical Condensed Matter Group in Grenoble (second year).

    BSc in Physics, University Pierre et Paris Curie, Paris (Paris 6)

Research

The usual sense of quantum computing is to use the tools of quantum mechanics in order to improve computer science. But the reverse is also true: use the tools of theoretical computer science to understand better some fundamental problems in the quantum physics, for example: quantum non-locality, or causality.

I love playing with this two topics, theoretical physic and computer science, which allow us to improve the both classical computer science and Quantum physics.

I am particularly  interested in everything connected with non-locality and causality correlation: non-local boxes, non-local games, characterization of non-local correlations with some resources...

But Non-local correlations are not only quantum: there are some correlations which are more "non-local" than the quantum ones, but which verify still the causality condition and... which are useful to find some lower bounds in classical computer science !
Publications
(Journal avec comité de lecture)

1. The communication complexity of non-signaling distributions Julien Degorre, Marc Kaplan, Sophie Laplante, and Jérémie Roland.

Quantum Information and Computation (Rinton Press), 2011  to appear (24 pages)

2. Classical simulation of traceless binary observables on any bipartite quantum state. Julien Degorre, Sophie Laplante, and Jeremie Roland.

Physical Review A, 75 :012309, 2007 (7 pages)

3. Simulating quantum correlations as a distributed sampling problem. Julien Degorre, Sophie Laplante, and Jeremie Roland.

Physical Review A, 72 :062314, 2005 (13 pages).

4. An intuitive approach for the simulation of quantum correlations. Julien Degorre and Jérémie Roland.

26th Symposium on Information Theory in the Benelux , p197-204, 2005. (8 pages).
(Conférence avec comité de lecture)

5. A combinatorial approach of non locality Julien Degorre, Mehdi Mhalla.

Recent Progress in the Theoretical and Experimental Foundations of Quantum Technology, Durdan 2010. (8 pages)

6. The communication complexity of non-signaling distributions, Julien Degorre, Marc Kaplan, Sophie Laplante, and Jérémie Roland.

In 34th International Symposium on Mathematical Foundations of Computer Science (MFCS’09), volume 5734 of Lecture Notes in Computer Science, pages 270-281. Springer, 2009 (11 pages)

7. Simulating causal distribution. Julien Degorre, Sophie Laplante, and Jeremie Roland. Quantum Information Processing (Q.I.P.) 2007. Delhi, India (20 pages)

8. Simulating quantum correlations as a distributed sampling problem. Julien Degorre, Sophie Laplante, and Jeremie Roland. Quantum Information Processing (Q.I.P.) 2006. Paris, France (14 pages)


Talks selection

Dec. 2010 From non-locality to causality -LTCI, Télécom ParisTech -invited Paris.

Sep. 2010 A combinatorial approach of non locality, Theoretical and Exp. Foundations of Quantum Technology, Durdan South Africa 2010

Dec. 2009 Non locality and combinatory -département d’informatique université Édimbourg, UK. Mai 2009 Non locality as a ressource -Laboratoire de Physique des particules LAPP-invité Annecy, France

Mars 2009 combinatorial approach of causality, Centre of Quantum Technologies, Invited, university of Singapore.

Juin 2008 Cerner la non localité quantique : des inégalités de Bell aux jeux non locaux ou Comment l’informatique théorique devient un outil au service de la physique ? Atelier Quantique Laboratoire louis Neel, CNRS Grenoble.

Avril 2008 Introduction to non local complexity -QICS conference Workshop Saint pierre en Chartreuse, France.

Nov 2007 : Caractériser la non-localité. -invité -L.I.G, CNRS Grenoble.

Août 2007 : Feynman au secours de la non-localité. -L.I.T.Q, Université de Montreal.

Août 2006 : Simulation of Bipartite Qudit Correlations -conference C.Q.I.S.C, Université de Calgary.

Janv. 2006 : Simulating quantum correlations as a distributed sampling problem Quantum Information Processing (Q.I.P.) 2006 -Paris

Fev. 2005 : La simulation des correlations quantiques se réduit à un problème d’échantillonnage. Université libre de Bruxelles, Bruxelles

Nov. 2005 : Simuler les correlations quantique Journée Quantique and Co. école Normale Supérieure, Lyon

Avr. 2005 : Simuler les mesures POVM e l’aide des boites non locales et de la communication L. I. T. Q. Université de Montréal, Montréal Juil.

2003 : Le pseudo-clonage quantique de qubits orthogonaux. L. I. T. Q. Université de Montréal, Montréal

Juin 2001 : Comportement quantique d’une jonction Josephson dans un environnement électromagnétique Laboratoire de Physique et Modélisation des Milieux Condenses, Grenoble

Nov. 2000 : Decoherence et gravitation, une explication plus profonde de la réduction du paquet d’onde Centre de Physique Théorique dans le cadre du " Relativity Lunch ", Marseille

Juin 2000 : Les différentes interprétations de la mécanique quantique et le problème de la mesure Université Joseph Fourier pour l’association " Physis Orbis ", Grenoble
Public lecture

Janv. 2006 : L’informatique quantique : la réalité dépasse-t-elle la fiction ? Conférencier invité Assemblée Générale de l’aDIRC (association des décideurs informatiques de la Région Centre), Orléans, France