The SEMPARIS seminar webserver hosts annoucements of all seminars taking place in Paris area, in all topics of physics, mathematics and computer science. It allows registered users to receive a selection of announcements by email on a daily or weekly basis, and offers the possibility to archive PDF or Powerpoint files, making it available to the scientific community. [ More information ]
Upcoming Seminars  
[ scheduler view ] 
Wednesday 19 June 2024, 11:00 at LKB, Room 2 – Collège de France – 11 Place Marcelin Berthelot – 75005  SEMLKB (Séminaire du Laboratoire Kastler Brossel)  quantph 



Abstract:  From 2010 to 2015, the gravitationalwave (GW) detector GEO600 was using squeezed light in all of its searches for GWs [1]. The successful sensitivity improvement triggered the implementation of “squeeze lasers” also in Advanced LIGO and Advanced Virgo. In 2019 they started their third observational run with an increased event rate of up to 50% due to the exploitation of squeezed states of light [2,3]. More recently, LIGO’s optical quantum noise was shown to be less than that at the Standard Quantum Limit (SQL) [4]. While a squeezed quantum uncertainty refers to quantum correlations in time, I will explain why the observation in [4] certifies correlations between the quantum uncertainties of the optical field and those of the motion of the 40 kg mirrors [5]. References : [1] LIGO Scientific Collaboration, Nature Physics 7, 962 (2011); [2] M. Tse et al., Phys. Rev. Lett. 123, 231107 (2019); [3] F. Acernese et al., Phys. Rev. Lett. 123, 231108 (2019); [4] H. Yu et al., Nature 583, 43 (2020); [5] R. Schnabel and M. Korobko, AVS Quantum Sci 4, 014701 (2022). 
Wednesday 19 June 2024, 12:45 at LPENS, 3 rue dUlm  FORUMENS (Forum de Physique Statistique @ ENS)  condmat.statmech 



Abstract:  TBA 
Wednesday 19 June 2024, 14:00 at LPTHE, LPTHE library, tower 1314, room 401  SEMEXCEP (Seminaire exceptionnel)  hepth 



Abstract:  I will explain how some recent progress on the WheelerDeWitt equation makes possible the systematic development of quantum cosmology in the canonical formulation. The cosmological wavefunctions are automorphic forms, and the WheelerDeWitt equation reduces to a dynamical equation on moduli space, so that quantum cosmology is equivalent to "automorphic dynamics". I will describe in detail this equivalence in the simple context of pure threedimensional gravity and comment on how these ideas should generalize to higher dimensions and to our universe. 
Wednesday 19 June 2024, 14:15 at IPHT, Salle Claude Itzykson, Bât. 774  IPHTMAT (Séminaire de matrices, cordes et géométries aléatoires)  hepth 



Abstract:  I will discuss recent progress in computing oneloop partition functions of strings in type II backgrounds with RR flux. The backgrounds we focus on are relevant for holographic setups with wellunderstood gauge theory duals. The computation of certain observables in the QFT duals can be done using supersymmetric localization to a matrix model. Using string theory, we will compute the expectation value of BPS Wilson loop operators in gauge theories and determine nonperturbative corrections to sphere partition functions and compare with QFT predictions when available. 
Thursday 20 June 2024, 10:00 at IHES, Amphithéâtre Léon Motchane  PTIHES (Séminaire de physique théorique de l'IHES)  hepth 



Abstract:  I will discuss two lattice avatars of ’t Hooft anomalies. The first one involves an action of a symmetry group on observables of a 1d spin system. It is related to a generalization of the LiebSchultzMattis theorem. The second one concerns symmetries of gapped states of spin systems. I will argue that the Hall conductance and other topological invariants of symmetric gapped states can be interpreted as obstructions to localizing the symmetry even approximately. 
Thursday 20 June 2024, 11:00 at
CDF,
Amphitheatre Halbwachs ( https://indico.in2p3.fr/event/32058/overview )  WORKCONF (Workshop or Conference)  hepth 



Abstract:  First day of LPENS Summer Institute, taking place at College de France 
Thursday 20 June 2024, 14:00 at
LPTMC,
LPTMC seminar room, Jussieu, towers 1213, 5th floor, room 523 ( [11] A.Jouan et al. Nature Elec. 3, 201–206 (2020). )  SEMEXCEP (Seminaire exceptionnel)  condmat 



Abstract:  [For the full abstract see the attached pdf]. A key feature of these electronic systems lies in the possibility to control their carrier density by electric field effect, which results in gatetunability of both superconductivity and Rashba spinorbit coupling. In this talk, I will review complementary dc and microwave transport measurements conducted on SrTiO3 and KTaO3based interfaces employing both backgate and topgate configurations. I will discuss, in particular, gateinduced multigap superconductivity [8,9] and the role of phase fluctuations within the BerezinskiiKosterlitzThouless model [10]. I will also present the realization of field effect devices whose physical properties, including superconductivity and Rashba spinorbit coupling, can be tuned over a wide range of electrostatic doping, and discuss the potential of oxides interfaces for the realization of mesoscopic devices [11].  
Attachments: 
Friday 21 June 2024, 10:00 at IPHT, Salle Claude Itzykson, Bât. 774  COURS (Cours)  physics 



Abstract:  The direct detection of gravitational waves from merging binary systems notoriously marked an important milestone in physics. Much of the success of gravitationalwave astronomy relies on perturbation theory. Perturbative approaches are essential ingredients in the study of gravitationalwave sources in the strongfield regime, such as the ringdown after the merger of a binary system, tidally perturbed compact objects, and extreme mass ratio inspirals.\\ \\ \\ The course will review selected topics in the context of black hole perturbation theory. The lectures will provide a pedagogical introduction to the main concepts and ideas, dating back to the original works by Regge and Wheeler in the 1950s, while covering also some of the more recent developments and results in the literature.\\ \\ Aspects to be discussed include:\\ \\ Introduction to black hole perturbation theory 
Friday 21 June 2024, 10:00 at
CDF,
Amphitheatre Halbwachs ( https://indico.in2p3.fr/event/32058/overview )  WORKCONF (Workshop or Conference)  hepth 



Abstract:  Second day of LPENS Summer Institute, taking place at College de France 
Saturday 22 June 2024, 11:00 at
LPENS,
Conf IV ( https://indico.in2p3.fr/event/32058/overview )  WORKCONF (Workshop or Conference)  hepth 



Abstract:  Third day of LPENS Summer Institute, taking place at LPENS 
Monday 24 June 2024, 11:00 at
LPENS,
Conf IV ( https://indico.in2p3.fr/event/32058/overview )  WORKCONF (Workshop or Conference)  hepth 



Abstract:  Fourth day of LPENS Summer Institute, taking place at LPENS 
Tuesday 25 June 2024, 11:00 at LPTMS, Salle des séminaires du FAST et du LPTMS  LPTMS (Séminaire du Laboratoire de Physique Théorique et Modèles Statistiques (Orsay))  condmat.statmech 


Tuesday 25 June 2024, 11:00 at
LPENS,
Conf IV ( https://indico.in2p3.fr/event/32058/overview )  WORKCONF (Workshop or Conference)  hepth 



Abstract:  Fifth day of LPENS Summer Institute, taking place at LPENS 
Tuesday 25 June 2024, 14:00 at IJCLAB, A018  NUCTHEO (Séminaire de physique nucléaire théorique)  nuclth 



Abstract:  Fewbody universality connects the properties of systems that are governed by interactions which generate large swave scattering lengths, $a_0$. In the first part of this talk I will argue that several twoneutron halo nuclei could display aspects of fewbody universality. In particular, I will show calculations of the twoneutron energy spectrum that is produced after rapid removal of the core from several exotic nuclei. After appropriate rescaling the resulting spectra are described by single curve, a result that is due to the proximity of the neutronneutron and coreneutron interactions to the unitary limit $a_0\to \infty$. In the second part of the talk I will discuss ab initio results for $^6$Li that were obtained using the NoCore Shell Model with Continuum (NCSMC). The NCSMC calculations show a strong correlation between the deuteron separation energy in $^6$Li and the Asymptotic Normalization Coefficient of the alphadeuteron component of its wave function. I will argue that this correlation is not a universal one, but that it is due to a factorization of longdistance and shortdistance physics in $^6$Li, and that this factorization can be exploited to make ab initio calculations of that system more efficient.  
Attachments: 
Wednesday 26 June 2024, 09:00 at
LPENS,
Amphitheatre Jean Jaurès, 29 rue d'Ulm, ENS ( https://indico.in2p3.fr/event/32058/overview )  WORKCONF (Workshop or Conference)  hepth 



Abstract:  Sixth day of LPENS Summer Institute, Celebration of Costas Bachas 
Wednesday 26 June 2024, 11:00 at LKB, Amphi Budé – Collège de France – 11 Place Marcelin Berthelot – 75005  SEMLKB (Séminaire du Laboratoire Kastler Brossel)  quantph 



Abstract:  Manybody correlations drive a variety of important quantum phenomena and quantum machines including superconductivity and magnetism in condensed matter as well as quantum computers. Understanding and controlling quantum manybody correlations is thus one of the central goals of modern science and technology. My research group has recently pioneered a novel pathway towards this goal with nearby ultracold atoms excited with an ultrashort laser pulse to a Rydberg state far beyond the Rydberg blockade regime [17]. We first applied our ultrafast coherent control with attosecond precision [2,3] to a random ensemble of those Rydberg atoms in an optical dipole trap, and successfully observed and controlled their strongly correlated electron dynamics on a subnanosecond timescale [1]. This new approach is now applied to arbitrary atom arrays assembled with optical lattices or optical tweezers that develop into a pathbreaking platform for quantum simulation and quantum computing on an ultrafast timescale [47]. In this ultrafast quantum computing, as schematically shown in Fig. 1, we have recently succeeded in executing a controlledZ gate, a conditional twoqubit gate essential for quantum computing, in only 6.5 nanoseconds at quantum speed limit, where the gate speed is solely determined by the interaction strength between two qubits [5]. This is faster than any other twoqubit gates with coldatom hardware by two orders of magnitude. It is also two orders of magnitude faster than the noise from the external environment and operating lasers, whose timescale is in general 1 microsecond or slower, and thus can be safely isolated from the noise. Moreover, this twoqubit gate is faster than the fast twoqubit gate demonstrated recently by “Google AI Quantum” with superconducting qubits [8]. References [1] N. Takei et al., Nature Commun. 7, 13449 (2016). Highlighted by Science 354, 1388 (2016); IOP PhyscisWorld.com (2016). [2] H. Katsuki et al., Acc. Chem. Res. 51, 1174 (2018). [3] C. Liu et al., Phys. Rev. Lett. 121, 173201 (2018). [4] M. Mizoguchi et al., Phys. Rev. Lett. 124, 253201 (2020). [5] Y. Chew et al., Nature Photonics 16, 724 (2022). (Front Cover Highlight) [6] V. Bharti et al., Phys. Rev. Lett. 131, 123201 (2023). [7] V. Bharti et al., arXiv:2311.15575 (2023). [8] B. Foxen et al., Phys. Rev. Lett. 125, 120504 (2020). 
Wednesday 26 June 2024, 12:45 at LPENS, College de France 3 rue dUlm  FORUMENS (Forum de Physique Statistique @ ENS)  condmat.statmech 



Abstract:  TBA 
Thursday 27 June 2024, 11:30 at
LPENS,
Conf IV ( https://indico.in2p3.fr/event/32058/overview )  WORKCONF (Workshop or Conference)  hepth 



Abstract:  Seventh day of LPENS Summer Institute 
Friday 28 June 2024, 10:00 at IPHT, Salle Claude Itzykson, Bât. 774  COURS (Cours)  physics 



Abstract:  The direct detection of gravitational waves from merging binary systems notoriously marked an important milestone in physics. Much of the success of gravitationalwave astronomy relies on perturbation theory. Perturbative approaches are essential ingredients in the study of gravitationalwave sources in the strongfield regime, such as the ringdown after the merger of a binary system, tidally perturbed compact objects, and extreme mass ratio inspirals.\\ \\ \\ The course will review selected topics in the context of black hole perturbation theory. The lectures will provide a pedagogical introduction to the main concepts and ideas, dating back to the original works by Regge and Wheeler in the 1950s, while covering also some of the more recent developments and results in the literature.\\ \\ Aspects to be discussed include:\\ \\ Introduction to black hole perturbation theory 
Friday 28 June 2024, 11:00 at
LPENS,
Conf IV ( https://indico.in2p3.fr/event/32058/overview )  WORKCONF (Workshop or Conference)  hepth 



Abstract:  Last day of LPENS Summer Institute 
Friday 28 June 2024, 14:00 at LPTHE, Library  LPTHEPPH (Particle Physics at LPTHE)  hepph 



Abstract:  In this talk I am going to present about my recent work on the thermal freezeout of a dark photon dark matter in the dark axion portal: a triple coupling among an axionlike particle, a dark photon, and the SM photon. We pay special attention to the coscattering regime (aka conversiondriven freezeout). Furthermore, we explore a few prospects of having the axion as a longlived particle, possibly to be searched at the LHC and future experiments. 
Wednesday 3 July 2024, 11:00 at LKB, Amphi Budé – Collège de France – 11 Place Marcelin Berthelot – 75005  SEMLKB (Séminaire du Laboratoire Kastler Brossel)  quantph 



Abstract:  Among platforms for storing quantum states in the microwave domain, solid state spin ensembles addressed via superconducting circuits stand out for their multimodal storage capability and the secondlong coherence time when operated at clock transitions [1]. Successful implementation of a practical memory scheme requires several keys features, such as the ability to tune ondemand the frequency and the bandwidth of the resonator [2]. In this talk, we will present a superconducting circuit architecture accomplishing both, allowing strong coupling to an ensemble of bismuth dopants in silicon. We devise a parametric process to dynamically control the virtual bandwidth of the superconducting circuit by exploiting its kinetic inductance nonlinearity, demonstrating coupling rate tuning range over a factor of 15. The strong coupling of the spins to the resonator also set radiation loss as the main nspin relaxation channel. Combined with nuclear and electronic drives, this Purcell effect enables to polarize the spins dynamically predominantly into a single ground state, allowing us to reach a cooperativity between the resonator and the spin ensemble near unity. [1] Wolfowicz, G. et al. Nature nanotechnology 8, 561–564 (2013). [2] Julsgaard, B. et al. Phys. Rev. Lett. 110, 250503 (2013). 
Friday 5 July 2024, 10:00 at IPHT, Salle Claude Itzykson, Bât. 774  COURS (Cours)  physics 



Abstract:  The direct detection of gravitational waves from merging binary systems notoriously marked an important milestone in physics. Much of the success of gravitationalwave astronomy relies on perturbation theory. Perturbative approaches are essential ingredients in the study of gravitationalwave sources in the strongfield regime, such as the ringdown after the merger of a binary system, tidally perturbed compact objects, and extreme mass ratio inspirals.\\ \\ \\ The course will review selected topics in the context of black hole perturbation theory. The lectures will provide a pedagogical introduction to the main concepts and ideas, dating back to the original works by Regge and Wheeler in the 1950s, while covering also some of the more recent developments and results in the literature.\\ \\ Aspects to be discussed include:\\ \\ Introduction to black hole perturbation theory 
Friday 12 July 2024, 10:00 at IPHT, Salle Claude Itzykson, Bât. 774  COURS (Cours)  physics 



Abstract:  The direct detection of gravitational waves from merging binary systems notoriously marked an important milestone in physics. Much of the success of gravitationalwave astronomy relies on perturbation theory. Perturbative approaches are essential ingredients in the study of gravitationalwave sources in the strongfield regime, such as the ringdown after the merger of a binary system, tidally perturbed compact objects, and extreme mass ratio inspirals.\\ \\ \\ The course will review selected topics in the context of black hole perturbation theory. The lectures will provide a pedagogical introduction to the main concepts and ideas, dating back to the original works by Regge and Wheeler in the 1950s, while covering also some of the more recent developments and results in the literature.\\ \\ Aspects to be discussed include:\\ \\ Introduction to black hole perturbation theory 

[ English version ] 