Presentation of IPhT : The Institute of Theoretical Physics (IPhT) is an Institute of the Direction of Fundamental Research (DRF) of the Commissariat for Atomic Energy and Alternative Energies (CEA).
2023 Galileo Galilei Medal for David Kosower (IPhT), Zvi Bern(California U) and Lance Dixon (SLAC)  


The 15th of February, birthday of Galileo Galilei, the 2023 Galileo Galilei Medal of INFN and GGI has been awarded "for the development of powerful methods for high-order perturbative calculations in quantum field theory" to David Kosower, researcher at the Institut de Physique Théorique, Zvi Bern(California U) and Lance Dixon (SLAC).


INFN Press release


E. De-laborderie, 2023-02-17 09:04:00


Quantum networks : Entangled ions across the university campus Innsbruck   


Trapped ions are one of the leading systems to build quantum computers. To link multiple such quantum systems, interfaces are needed through which the quantum information can be transmitted. Until now, trapped ions were only entangled with each other over a few meters in the same laboratory. Researchers from the university of Innsbruck succeeded to entangle two trapped ions located in two labs separated  by 230 meters. These efforts have been supported by a theoretical model of a single trapped ion including most of experimental noise sources.

The model, developed at IPhT, provided a guidance for the experimentalists, showing for example what to expect when increasing the distance or helping to identify the most detrimental noise sources. With the entanglement of far away ions, Austrian researchers show that trapped ions are a promising platform for future quantum networks that span cities and eventually continents. The results have been published in Physical Review Letters. They have been highlighted by Editors’ Suggestion and a Synopsis in Physics. 


Entanglement of trapped-ion qubits separated by 230 meters

See also the Synopsis 

Highlight on the CEA/DRF site



E. De-laborderie, 2023-02-10 15:11:00


Hamiltonian paths, a challenge for KPZ.  




Examples of measured exponents and their comparison to KPZ predictions, before and after renormalization

    The famous KPZ formulas (Knizhnik-Polyakov-Zamolodchikov, 1988) relate the critical exponents of statistical models on regular two-dimensional lattices to the exponents of the same models on planar random lattices. These relations, verified exactly in a large number of statistical mechanics systems, have now acquired a rigorous mathematical status, under certain technical assumptions of statistical independence. Hamiltonian paths on lattices, which are self-avoiding paths forced to visit all the sites of the lattice, constitute a critical statistical model where the geometrical constraints are particularly strong. A team at IPhT studied the case of the honeycomb lattice and its random counterpart, the bicubic lattice (a bipartite lattice made only of trivalent vertices colored in black and white so that the vertices of one color are connected only to those of the other color). The critical exponents in the first case are computed by standard Coulomb gas methods, while the critical exponents in the second case can be obtained numerically with a high accuracy from the exact enumeration of Hamiltonian path configurations for finite size lattices.

Surprisingly, the expected KPZ relations fail for some types of critical exponents, indicating that a new mechanism is at work which goes beyond their usual scope of application! A procedure (heuristic at this stage) of renormalization (readjustment of the KPZ formulas with a new parameter) is proposed which seems to restore the validity of these relations. The challenge is now to understand mathematically how the particular geometrical constraints of the Hamiltonian paths can influence the statistics of the bipartite random lattice, and lead to such a renormalization.

Ref: P. Di Francesco, B. Duplantier, O. Golinelli and E. Guitter, Exponents for Hamiltonian paths on random bicubic maps and KPZ arXiv :2210/08887 [math-ph]

E. De-laborderie, 2023-02-03 15:19:00


SLE multifractal news

2022-04-05 11:28:00

Arrival of Pierre Fleury

2022-02-01 09:21:00

An strongly secured encryption

2020-09-17 17:01:00

Mon, Mar. 20th, 11:00-12:00
Séminaire de physique mathématique - Jules Lamers
Tue, Mar. 21st, 10:00-12:30
Groupe de travail - Haggai Landa
Tue, Mar. 21st, 14:00-15:00
Séminaire de physique des particules et de cosmologie - Marco Gorghetto
Wed, Mar. 22nd, 14:15
Séminaire de matrices, cordes et géométries aléatoires - Alejandra Castro
Thu, Mar. 23rd, 11:30-12:30
Séminaire de physique des particules et de cosmologie - Federica Guidi
François David
Presentation of IPhT
Catherine Pépin
What is so facinating about supraconductivity?
David Kosower
Precision Calculations in the Search for Unification


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