University of Warsaw

About: University of Warsaw is a education organization based out in Warsaw, Poland. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 20832 authors who have published 56617 publications receiving 1185084 citations. The organization is also known as: Uniwersytet Warszawski & Warsaw University.

Directed spontaneous emission from an extended ensemble of N atoms: timing is everything.

Abstract: A collection of $N$ static atoms is fixed in a crystal at a low temperature and prepared by a pulse of incident radiation of wave vector ${\stackrel{\ensuremath{\rightarrow}}{k}}_{0}$. The $N$ atoms are well described by an entangled Dicke-like state, in which each atom carries a characteristic phase factor $\mathrm{exp} (i{\stackrel{\ensuremath{\rightarrow}}{k}}_{0}\ifmmode\cdot\else\textperiodcentered\fi{}{\stackrel{\ensuremath{\rightarrow}}{r}}_{j})$, where ${\stackrel{\ensuremath{\rightarrow}}{r}}_{j}$ is the atomic position in the crystal. It is shown that a single photon absorbed by the $N$ atoms will be followed by spontaneous emission in the same direction. Furthermore, phase matched emission is found when one photon is absorbed by $N$ atoms followed by two-photon down-conversion.

Stability of flux compactifications and the pattern of supersymmetry breaking

Abstract: We extend the KKLT approach to moduli stabilization by including the dilaton and the complex structure moduli into the effective supergravity theory. Decoupling of the dilaton is neither always possible nor necessary for the existence of stable minima with zero (or positive) cosmological constant. The pattern of supersymmetry breaking can be much richer than in the decoupling scenario of KKLT.

Six months of multiwavelength follow-up of the tidal disruption candidate asassn-14li and implied tde rates from asas-sn

Abstract: We present ground-based and Swift photometric and spectroscopic observations of the candidate tidal disruption event (TDE) ASASSN-14li, found at the center of PGC043234 (d ' 90 Mpc) by the All-Sky Automated Survey for SuperNovae (ASAS-SN). The source had a peak bolometric luminosity of L ' 1044 ergs s

Mistargeted mitochondrial proteins activate a proteostatic response in the cytosol

Abstract: Most of the mitochondrial proteome originates from nuclear genes and is transported into the mitochondria after synthesis in the cytosol. Complex machineries which maintain the specificity of protein import and sorting include the TIM23 translocase responsible for the transfer of precursor proteins into the matrix, and the mitochondrial intermembrane space import and assembly (MIA) machinery required for the biogenesis of intermembrane space proteins. Dysfunction of mitochondrial protein sorting pathways results in diminishing specific substrate proteins, followed by systemic pathology of the organelle and organismal death. The cellular responses caused by accumulation of mitochondrial precursor proteins in the cytosol are mainly unknown. Here we present a comprehensive picture of the changes in the cellular transcriptome and proteome in response to a mitochondrial import defect and precursor over-accumulation stress. Pathways were identified that protect the cell against mitochondrial biogenesis defects by inhibiting protein synthesis and by activation of the proteasome, a major machine for cellular protein clearance. Proteasomal activity is modulated in proportion to the quantity of mislocalized mitochondrial precursor proteins in the cytosol. We propose that this type of unfolded protein response activated by mistargeting of proteins (UPRam) is beneficial for the cells. UPRam provides a means for buffering the consequences of physiological slowdown in mitochondrial protein import and for counteracting pathologies that are caused or contributed by mitochondrial dysfunction.

The flavor of the composite pseudo-goldstone Higgs

Abstract: We study the flavor structure of 5D warped models that provide a dual description of a composite pseudo-Goldstone Higgs. We first carefully re-examine the flavor constraints on the mass scale of new physics in the standard Randall-Sundrum-type scenarios, and find that the KK gluon mass should generically be heavier than about 21 TeV. We then compare the flavor structure of the composite Higgs models to those in the RS model. We find new contributions to flavor violation, which while still are suppressed by the RS-GIM mechanism, will enhance the amplitudes of flavor violations. In particular, there is a kinetic mixing term among the SM fields which (although parametrically not enhanced) will make the flavor bounds even more stringent than in RS. This together with the fact that in the pseudo-Goldstone scenario Yukawa couplings are set by a gauge coupling implies the KK gluon mass to be at least about 33 TeV. For both the RS and the composite Higgs models the flavor bounds could be stronger or weaker depending on the assumption on the value of the gluon boundary kinetic term. These strong bounds seem to imply that the fully anarchic approach to flavor in warped extra dimensions is implausible, and there have to be at least some partial flavor symmetries appearing that eliminate part of the sources for flavor violation. We also present complete expressions for the radiatively generated Higgs potential of various 5D implementations of the composite Higgs model, and comment on the 1–5 percent level tuning needed in the top sector to achieve a phenomenologically acceptable vacuum state.