Upper bound for the grand canonical free energy of the Bose gas in the Gross-Pitaevskii limit

We consider a homogeneous Bose gas in the Gross-Pitaevskii limit at temperatures that are comparable to the critical temperature for Bose-Einstein condensation in the ideal gas. Our main result is an upper bound for the grand canonical free energy in terms of two new contributions: (a) the free energy of the interacting condensate is given in terms of an effective theory describing its particle number fluctuations, (b) the free energy of the thermally excited particles equals that of a temperature-dependent Bogoliubov Hamiltonian.Comment: 41 page

Optimal Rate for Bose-Einstein Condensation in the Gross-Pitaevskii Regime

We consider systems of bosons trapped in a box, in the Gross-Pitaevskii regime. We show that low-energy states exhibit complete Bose-Einstein condensation with an optimal bound on the number of orthogonal excitations. This extends recent results obtained in \cite{BBCS1}, removing the assumption of small interaction potential.Comment: 99 pages, typos correcte

17,β-estradiol inhibits hepatitis C virus mainly by interference with the release phase of its life cycle

Rationale & Aim: Estrogen and estrogen-mediated signalling protect from hepatitis C virus through incompletely understood mechanisms. We aimed to ascertain which phase(s) of HCV life cycle is/are affected by estrogens. Methods: Huh7 cells infected with the JFH1 virus (genotype 2a) were exposed to dehydroepiandrosterone, testosterone, progesterone and 17β-estradiol (tested with/without its receptor antagonist fulvestrant). Dose-response curves were established to calculate IC50 values. To dissect how 17β-estradiol interferes with phases of HCV life cycle, its effects were measured on the HCV pseudo-particle system (viral entry), the sub-genomic replicon N17/JFH1 and the replicon cell line Huh7-J17 (viral replication). Finally, in a dual-step infection model, infectious supernatants, collected from infected cells exposed to hormones, were used to infect naïve cells. Results: Progesterone and testosterone showed no inhibitory effect on HCV; dehydroepiandrosterone was only mildly inhibitory. In contrast, 17β-estradiol inhibited infection by 64-67% (IC50 values 140 to 160 nM). Fulvestrant reverted the inhibition by 17β-estradiol in a dose-dependent manner. 17β-estradiol exerted only a slight inhibition (<20%) on HCV pseudo-particles, and had no effect on cells either transiently or stably (Huh7-J17 cells) expressing the N17/JFH1 replicon. In the dual-step infection model, a significant IC50 decline occurred between primary (134 nM) and secondary (100 nM) infections (p=0.02), with extracellular HCV RNA and infectivity being reduced to a higher degree in comparison to its intracellular counterpart. Conclusions: 17β-estradiol inhibits HCV acting through its intracellular receptors, mainly interfering with late phases (assembly/release) of the HCV life cycle

Into the Un(Known). Unveiling Science's intrinsic Art

Entrerete in un mondo nuovo e quasi astratto, apparentemente innaturale. Sarete circondati da suoni e immagini familiari e allo stesso tempo distanti dalla vostra quotidianità. Gli eventi in cui vi troverete immersi sono comuni nella vita di tutti i giorni, anche se non li riconoscete perché “silenziati”. Sono, infatti, fenomeni che acquistano importanza su scale molto grandi, cosmiche potremmo dire, e in condizioni fisiche incompatibili con la vita umana. A raccontarvi questo meraviglioso mondo sarà la “voce” familiare della luce, la radiazione elettromagnetica prodotta dalle varie sorgenti astrofisiche sparse nell’Universo, il principale canale di comunicazione a disposizione degli astronomi per indagare i più reconditi segreti del Cosmo. La luce, esploratrice instancabile, ci racconta gli scenari in cui è stata generata: esplosioni di Supernovae, materia che cade in un buco nero, brillamenti solari, e molto altro. Fenomeni lontani e misteriosi che sfuggono alla nostra esperienza diretta, ma che da anni sono al centro delle ricerche scientifiche più avanzate. Preparatevi ad entrare nell'ignoto, lasciate che la luce vi mostri l'invisibile

The excitation spectrum of the Bose gas in the Gross-Pitaevskii regime

We consider a gas of interacting bosons trapped in a box of side length one in the Gross–Pitaevskii limit. We review the proof of the validity of Bogoliubov’s prediction for the ground state energy and the low-energy excitation spectrum. This note is based on joint work with C. Brennecke, S. Cenatiempo and B. Schlein

Quantum many-body fluctuations around nonlinear Schrödinger dynamics

We consider the many-body quantum dynamics of systems of bosons interacting through a two-body potential $N^{3\beta−1}V(N^{\beta}x)$, scaling with the number of particles $N$. For $0<\beta<1$, we obtain a norm-approximation of the evolution of an appropriate class of data on the Fock space. To this end, we need to correct the evolution of the condensate described by the one-particle nonlinear Schrödinger equation by means of a fluctuation dynamics, governed by a quadratic generator