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DTSTART;TZID=Europe/Paris:20251014T140000
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DTSTAMP:20260503T035248
CREATED:20251013T085956Z
LAST-MODIFIED:20251013T125941Z
UID:11648-1760450400-1760454000@fermi.univ-tlse3.fr
SUMMARY:Hybrid between biologically inspired and quantum-inspired many-body states. -(Miha Srdinšekr / LPT / Seminar). - 14/10/2025\, 14H
DESCRIPTION:Séminaire LPT \nMiha Srdinšek (CEA) \nSeminar LPT\, 14/10/2025\, 14H\, 3R4\, salle de conférence \nSummary \nDeep neural networks can represent very different sorts of functions\, including complex quantum many-body states. Tensor networks can also represent these states\, have more structure and are easier to optimize. However\, they can be prohibitively costly computationally in two or higher dimensions. Here\, we propose a generalization of the perceptron – the perceptrain – which borrows features from the two different formalisms. We construct variational many-body ansatz from a simple network of perceptrains. The network can be thought of as a neural network with a few distinct features inherited from tensor networks. These include efficient local optimization akin to the density matrix renormalization algorithm\, instead of optimizing of all the parameters at once; the possibility to dynamically increase the number of parameters during the optimization; the possibility to compress the state to avoid overfitting; and a structure that remains quantum-inspired. We showcase the ansatz using a combination of Variational Monte-Carlo (VMC) and Green Function Monte-Carlo (GFMC) on a 10×10 transverse field quantum Ising model with a long range 1/r^6 antiferromagnetic interaction. The model corresponds to the Rydberg (cold) atoms platform proposed for quantum annealing. We consistently find a very high relative accuracy for the ground state energy\, around 10^{-5} for VMC and 10^{-6} for GFMC in all regimes of parameters\, including in the vicinity of the quantum phase transition. We used very small ranks (~2÷5 ) of perceptrains\, as opposed to multiples of thousand used in matrix product states. The optimization of the energy was robust with respect to the choice of initial conditions and hyper-parameters\, in contrast to a common experience when using neural network wave functions.
URL:https://fermi.univ-tlse3.fr/event/hybrid-between-biologically-inspired-and-quantum-inspired-many-body-states-miha-srdinsekr-lpt-seminar-14-10-2025-14h/
LOCATION:Salle de conférence\, Bâtiment 3R4
CATEGORIES:Events,LPT,Seminars
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DTSTART;TZID=Europe/Paris:20251021T140000
DTEND;TZID=Europe/Paris:20251021T153000
DTSTAMP:20260503T035248
CREATED:20251015T132553Z
LAST-MODIFIED:20251015T132553Z
UID:11723-1761055200-1761060600@fermi.univ-tlse3.fr
SUMMARY:Mouvements collectifs et contrôle externe dans des gouttes actives. -(Gabriel Ramos / LPT / Seminar). - 21/10/2025\, 14H
DESCRIPTION:Séminaire LPT \nGabriel Ramos (Softmat Toulouse) \nSeminar LPT\, 21/10/2025\, 14H\, 3R4\, salle de conférence \nSummary\nThe collective motions performed by self propelled particles\, such as flocks of birds or schools of fish\, are studied in physics within the domain of active matter. Using the precision and low cost of microfluidics\, living and synthetic microparticles have become an ideal playground to study these active matter systems. \nIn this talk\, we will present two experiments using bacterial suspensions to produce active droplets. The objective of these experiments is to understand how the local-scale microactivity (the collective motions resulting from bacterial-self-organization) is able to perform macromovements at the scale of the confining droplet\, which is about 100 times the size of a single bacterium. In other words\, we study how we can extract useful work from these confined suspensions. \nFirst\, we will show that the confinement of a suspension of Escherichia coli (E. coli) in a water-in-oil emulsion leads to bacterially propelled droplets that perform a persistent random walk. Secondly\, we will show that under the action of a constant magnetic field\, magnetotactic bacteria (MTB) confined in a water-in-oil emulsion self-assemble into a rotary motor that applies a torque on the external oily phase. A vortex collective motion is formed at the scale of the confining droplet size\, which is perpendicular to the magnetic field and is reversible when inverting the magnetic field direction. Finally\, we will briefly introduce a synthetic system of active droplets using liquid crystals\, showing their ability to reproduce living features such as chemotaxis\, light sensing and collective motions.
URL:https://fermi.univ-tlse3.fr/event/mouvements-collectifs-et-controle-externe-dans-des-gouttes-actives-gabriel-ramos-lpt-seminar-21-10-2025-14h/
LOCATION:Salle de conférence\, Bâtiment 3R4
CATEGORIES:Events,LPT,Seminars
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