IEA SERINT

IEA SERINT

French-Australian International Emerging Action on Physics

IEA SERINT
2018
Contact:

Dr. Jean-Marie Maillard
jean-marie.maillard(at)sorbonne-universite.fr

IEA SERINT
News

Zeroes of the partition function of the square Ising model in a magnetic field.

Equimodular curves of the square Ising model in a magnetic field.

Zeroes of the partition function of the square Ising model in a magnetic field.

Singularities of D-finite n-fold integrals associated to the suceptibility of the square Ising model.

Effective algebraic geometry: rational points of an algebraic surface in 15 dimensions generated by birational symmetries.

Effective algebraic geometry: rational points of an algebraic surface in 15 dimensions generated by birational symmetries.

Introduction

The IEA SERINT managed by Dr Jean-Marie Maillard (LPTMC, UMR 7600, CNRS – Sorbonne Université, Paris) in collaboration with the Department of Mathematics & Statistics, The University of Melbourne, Parkville Vic. Australia (Contact: Prof. A. J. Guttmann) is effective since 2018.

    Missions and research themes

    Series with integer coefficients emerge quite naturally in lattice statistical mechanics and enumerative combinatorics, the celebrated two-dimensional Ising model being the perfect illustration of this occurrence.  One remarks that such series are quite often solutions of linear and non-linear differential equations and have quite intriguing mathematical properties corresponding to different domain of mathematics (arithmetic, number theory, differential algebra, algebraic geometry, …).  Along this line, we had shown that the n-fold integrals occurring in theoretical physics are naturally diagonals of rational functions and this explains most of the intriguing and quite unexpected properties of so many physical quantities (reduction of the corresponding series with integer coefficients to algebraic functions modulo primes or power of primes, the series being solutions of globally nilpotent operators, …).

    The goal of IEA SERINT is to understand the intriguing mathematical properties of such series with integer coefficients emerging in theoretical physics. In particular we want to see if such series are essentially associated with some integrability properties of the models, or correspond to a larger framework. More precisely, we want to see if they mostly correspond to (holonomic, D-finite) linear differential equations, if they can correspond to selected (differentially algebraic) non-linear differential equations, or if they can  also  correspond to a much larger (differentially transcendental) framework. Consequently, the IEA SERINT is naturally organised according to these miscellaneous “dualities”: linear versus non-linear differential equations, integrability versus non-integrability, differentially algebraic versus differentially transcendental.

    It is also organised according to the various  well-suited mathematical domains and tools: differential algebra (creative telescoping approach), formal calculations  (DEtools in Maple, gfun), effective algebraic geometry and mod. prime calculations, analytic calculations (random theory, Stieltjes series), etc …

    MAIN PROJECTS OF RESEARCH

    We first obtained results in the simplest holonomic (i.e. linear) framework, revisiting a large set of non trivial results for diagonals of rational functions and series solutions of “telescopers” with a more intrinsic effective algebraic geometry approach. This sheds some light on the frequent and remarkable occurrence of modular forms in so many non-trivial examples in theoretical physics.

    We also made some important progress on the so-called “Christol’s conjecture” which amounts to conjecturing that any holonomic series with integer coefficients, and a finite radious of convergence, is a diagonal of a rational function. In a more enumerative combinatorics framework we revisited the occurrence of Stieltjes series, namely series with positive integer coefficients which can be seen as moments of an underlying measure, considering selected examples of enumerative combinatorics (pattern avoiding permutations). The exact calculations we performed in a holonomic (sometimes modular form) framework shed some light on relations of such series with positive integer coefficients  with various mathematical structures (random matrix theory, orthogonal polynomials, Hankel/Toeplitz matrices, …). 

    One notes that these relations may also work in a much larger non-holonomic framework. We still need to get results corresponding to a deeper understanding of differentially algebraic series with integer coefficients. Along this line we have already obtained some quite puzzling results for two-point correlation functions of the square Ising model: for a particular subcase of these two-point correlation functions we have seen  they are actually solutions of a two-parameter family of non-linear ODEs with the Painlevé property (fixed critical points), which corresponds exactly to sigma forms of Painlevé VI.

    A lot of work remains to be done in the general cases. Can we simply describe the non-linear ODEs with the Painlevé property for the general  two-point correlation funtions ? Are the corresponding series Stieltjes series ? Do the corresponding series reduce to algebraic functions modulo primes, or power of primes ?

    institutions and laboratories involved

    France

    Australia

    READ MORE

    IEA QUAP

    IEA QUAP

    French-Australian International Emerging Action in solid-state quantum optics.

    IEA QUAP
    2019-2021

    Contacts:
    France:
    Dr. Maxime ; maxime.richard@neel.cnrs.fr

    Australia:
    Prof. Thomas Volz ; thomas.volz@mq.edu.au

    fig.X – Artist representation of the open fibre-based microcavity system: the end surface of an optical fiber (top of the image) presents an indentation (a concave spherical shape) in the region of the fiber core, which is coated with a highly reflective Bragg mirror. A half-cavity lies below with a semiconductor quantum well embedded in the cavity layer (white slab), and the bottom Bragg mirror below (layers below). (Figure credit: Andrew Wood)

    Introduction

    IEA QUAP stand for Quantum Polaritonics. In the present context of blooming quantum technologies, the need for practical sources of quantum light are is pressing. The most developed solid-state systems proposed so far rely on advanced semiconductor nanotechnologies, in which nanometer-scale potential traps are engineered in order to confine electronic excitations into the quantum regime. The aim of QUAP is to explore an alternative strategy in which the electronic confinement is not required. The quantum regime is instead achieved by engineering a large Coulomb interaction between the electronic excitations, and stronger interaction with light. Such systems have the potential to be simple to fabricate and would be tunable to a much higher degree.

    THE IDEA

    Exciton-polaritons are hybrid states that are half photonic and half electron-hole in nature. They are engineered in a particular semiconductor optical microcavity design, in which the so-called “strong coupling regime” is achieved. Owing to their photonic nature,  polaritons provide a direct interface with light. Owing to their electronic nature, they are subject to strong Coulomb interaction with each other.

    When these interactions are strong enough, the presence of a polariton inside the cavity shifts its resonance, such that a second polariton cannot be created. This is the so-called regime of Coulomb blockade for polaritons[1]. In implementing this strategy, the challenge is to maximize the magnitude of this interaction, which is general not large enough as is. In QUAP our aim is to implement this strategy and enhance the interaction by photonic confinement, i.e. at the micrometer scale.

    This is done in a in a confocal open fiber-based microcavity in the strong coupling regime, in which a one micrometer polaritonic mode volume is achieved, without introducing additional radiative losses that would be detrimental to the blockade mechanism[2]. A sketch of this microcavity is shown in Fig.X (on the left side of this page). In order to get deep into the quantum regime, we also plan to shrink further this mode volume by the introduction of intracavity polaritonic lenses.

    [1] A. Verger, C. Ciuti, & I. Carusotto, I. Polariton quantum blockade in a photonic dot, Phys. Rev. B 73, 193306 (2006).

    [2] B. Besga et al. Polariton Boxes in a Tunable Fiber Cavity, Phys. Rev. Applied 3, 014008 (2015).

    Collaboration

    The experiments take place in the group of prof. Thomas Volz and his team at Macquarie Uni., Sydney, where the fiber-microcavity is being developed. With the support of the Australian Research Council (ARC)’s center of excellence for engineered quantum system (EQUS), Macquarie University, and CNRS’s International Emerging Actions, Maxime Richard and Thomas Volz have built up a very active collaboration which is based on the complementarity of their expertise in solid-state quantum optics. This collaborative knowledge has proven so far the key enabler in this and other projects.

    institutions and laboratories involved

    France:
    • Dr Maxime Richard (Institut Néel, CNRS – Université Grenoble Alpes – Grenoble INP)

    Australia:
    • Prof. Thomas Volz (Macquarie University)

    NEWS

    Very recently, we were able to demonstrate for the first time the build-up of weak quantum correlations in this system. Interestingly, another group led by Prof. A. Imamoğlu obtained simultaneously a quantitatively nearly identical result, in a similar fiber-cavity system[1]. We published the two results as two back-to-back articles in Nature Materials :

    1. Muñoz-Matutano, A. Wood, M. Johnson, X. Vidal Asensio, B. Baragiola, A. Reinhard, A. Lemaître, J. Bloch, A. Amo, B. Besga, M. Richard and T. Volz “Quantum-correlated photons from semiconductor cavity polaritons”, Nature Materials 18, 213–218 (2019)

    https://doi.org/10.1038/s41563-019-0281-z

    [1] A. Delteil et al. Nature Materials, 18, 219 (2019)

     

    IEA CosmoGravity

    IEA CosmoGravity

    French-Thai International Emerging Action in New challenges for cosmology and gravitation

    IEA (PICS 07964) CosmoGravity

    2018-2020

    Prof. Ignatios Antoniadis
    antoniad(at)lpthe.jussieu.fr

    Prof. Auttakit Chatrabhuti
    Auttakit.C(at)chula.ac.th

    IEA CosmoGravity
    Videos

    IEA CosmoGravity
    News

    Introduction

    The PICS  CosmoGravity (New challenges for cosmology and gravitation), managed by Prof. Ignatios Antoniadis (CNRS, Laboratoire de Physique Theorique et Haute Energies, Sorbonne Universite, Faculte des Sciences, Campus Jussieu) in collaboration with Physics Department of Chulalongkorn University (Prof. Auttakit Chatrabhuti), Bangkok, is effective in 2018, 2019 and 2020.

    Missions and research themes

    The project is devoted to study  present challenges in gravity and cosmology, with emphasis a new approach to mass scale hierarchies, in view of the experimental and theoretical state-of-the art. We have recently entered an unprecedented era, with the CERN Large Hadron Collider (LHC) searching for new particles and interactions at energies ten times Present and forthcoming particle physics and cosmological data have a real chance of pointing to a deeper and more refined microscopic high-energy theory. We plan to develop and combine ideas and techniques from supersymmetry, string theory, extra dimensions and holography to make progress in this direction. Central questions are: (i) the origin of the different scales associated with a theory describing cosmology, gravitation and particle physics; (ii) the role of supersymmetry at a fundamental level and its possible non-linear realisation at low energies. 

    MAIN projects of research

    The main research objectives are: (1) Particle physics and cosmology of (approximate) de Sitter vacua in supergravity, towards the description of both inflation and present dark energy. (2) Non-linear supersymmetry and cosmology. (3) The Universe through gravitational waves. 

    Our methodology relies heavily on effective field theory, symmetries and supergravity techniques. The results should be relevant to the ongoing and future observational programs in cosmology and gravitation, as well as to particle physics experiments searching for new physics beyond the Standard Model. In particular, we aim to identify interesting connections between cosmological observations, primordial gravitational waves and LHC results.

    institutions and laboratories involved

    France:
    • Ignatios Antoniadis (LPTHE – CNRS – Sorbonne Universite, Faculte des Sciences, Campus Jussieu, Pari

    Thailand

    • Auttakit Chatrabhuti (Physics Department, Chulalongkorn University, Bangkok)

     

    Ignatios Antoniadis (front row, center)  and Auttakit Chatrabhuti (front row, on the left) at a conference (Unveiling the fundamental laws of Nature), along with students. 

    Ignatios Antoniadis and Auttakit Chatrabhuti (front row) at the Bangkok school on high-energy physics. 

    IRL MAJULAB

    IRL MAJULAB

    International Research Laboratory between France and Singapore in Quantum Technologies, Quantum Computing, Photonics, Material Science

    IRL MajuLab

    Creation date: 2014
    Contact:
    Dr. Christian Miniatura
    direction(at)majulab.cnrs.fr

    IRL MajuLab     Website

    Yianing Li, Mehedi Hasan and David Wilkowski, tuning the laser system for cold atom experiments. Credits: Singapore

    Full view of the laser system for cold atom experiments. Credits: CQT, Singapore

    Cloud of magneto-optically trapped Strontium atoms (blue spot). Credits: CQT, Singapore

    Introduction

    The signing institutions of the IRL MajuLab are CNRS, Université Côte d’Azur, Sorbonne Université, National University of Singapore and Nanyang Technological University of Singapore. The IRL Majulab is currently directed by Dr Christian Miniatura (CNRS). It is one of the 75 IRL developed by the CNRS with strategic partners across the world and one of the 5 IRL in Singapore.

    In Singapore, the historical partner labs are Centre for Quantum Technologies (NUS) and School of Physical and Mathematical Sciences (NTU).

    In France, the historical partner labs are INPHYNI (UCA) and Laboratoire Kastler-Brossel (SU).

    Mission and research themes

    Mission: Bridge top researchers and labs of CNRS, UCA, SU, NUS and NTU into fruitful collaborative links and networks around selected topics in physics with a strong hold on quantum technologies.

    Research Axes : Quantum Matter, Quantum Information, Quantum Computing, Quantum Devices and Materials.

    MAIN projects of research

    QuantAlgo – Quantum Algorithms (2018 -2021)

    QND Measurement on Lattice Atom Interferometers with an Optical Clock Transition (2018-2021)

    Energetics of fault tolerant quantum computation (2019-2021)

    Visualizing Perovskite Growth to Unlock Optoelectronic Secrets (2020-2023)

    Unconventional magnetism and magneto-transport in chiral metallic magnets (2020-2023)

    laboratories involved

    France:
    Université Côte d’Azur: INPHYNI, CRHEA

    Sorbonne Université: LKB, LPENS, LPTMC, LIP6

    Université Grenoble Alpes: INSTITUT NEEL, LPM2C

    Université Toulouse III: LPT, LCAR

    Université de Bordeaux: LP2N

    Université Cergy Pontoise: LPTM

    Singapore:

    National University of Singapore: CQT, CA2DM, DPT of PHYSICS

    Nanyang Technological University: SPMS (PAP), MSE, CDPT

    Yale-NUS: Science Division

    SUTD: Science and Maths Cluster