3,022 research outputs found
Experimental Status Report on Vector Meson Spectroscopy
The experimental status of light vector meson spectroscopy is discussed. The
last results of experiments obtained at the VEPP-2M collider in
Novosibirsk are described and the comparison with the old data in the mass
region from 1 GeV to 2.5 GeV is performed.Comment: 6 pages, 13 figures, e^+e^- Physics at Intermediate Energies,
Workshop - Contribution T0
Assessing T cell clonal size distribution: a non-parametric approach
Clonal structure of the human peripheral T-cell repertoire is shaped by a
number of homeostatic mechanisms, including antigen presentation, cytokine and
cell regulation. Its accurate tuning leads to a remarkable ability to combat
pathogens in all their variety, while systemic failures may lead to severe
consequences like autoimmune diseases. Here we develop and make use of a
non-parametric statistical approach to assess T cell clonal size distributions
from recent next generation sequencing data. For 41 healthy individuals and a
patient with ankylosing spondylitis, who undergone treatment, we invariably
find power law scaling over several decades and for the first time calculate
quantitatively meaningful values of decay exponent. It has proved to be much
the same among healthy donors, significantly different for an autoimmune
patient before the therapy, and converging towards a typical value afterwards.
We discuss implications of the findings for theoretical understanding and
mathematical modeling of adaptive immunity.Comment: 13 pages, 3 figures, 2 table
Quantum jumps on Anderson attractors
In a closed single-particle quantum system, spatial disorder induces Anderson
localization of eigenstates and halts wave propagation. The phenomenon is
vulnerable to interaction with environment and decoherence, that is believed to
restore normal diffusion. We demonstrate that for a class of experimentally
feasible non-Hermitian dissipators, which admit signatures of localization in
asymptotic states, quantum particle opts between diffusive and ballistic
regimes, depending on the phase parameter of dissipators, with sticking about
localization centers. In diffusive regime, statistics of quantum jumps is
non-Poissonian and has a power-law interval, a footprint of intermittent
locking in Anderson modes. Ballistic propagation reflects dispersion of an
ordered lattice and introduces a new timescale for jumps with non-monotonous
probability distribution. Hermitian dephasing dissipation makes localization
features vanish, and Poissonian jump statistics along with normal diffusion are
recovered.Comment: 6 pages, 5 figure
Photon waiting time distributions: a keyhole into dissipative quantum chaos
Open quantum systems can exhibit complex states, which classification and
quantification is still not well resolved. The Kerr-nonlinear cavity,
periodically modulated in time by coherent pumping of the intra-cavity photonic
mode, is one of the examples. Unraveling the corresponding Markovian master
equation into an ensemble of quantum trajectories and employing the recently
proposed calculation of quantum Lyapunov exponents [I.I. Yusipov {\it et al.},
Chaos {\bf 29}, 063130 (2019)], we identify `chaotic' and `regular' regimes
there. In particular, we show that chaotic regimes manifest an intermediate
power-law asymptotics in the distribution of photon waiting times. This
distribution can be retrieved by monitoring photon emission with a
single-photon detector, so that chaotic and regular states can be discriminated
without disturbing the intra-cavity dynamics.Comment: 7 pages, 5 figure
Anderson localization or nonlinear waves? A matter of probability
In linear disordered systems Anderson localization makes any wave packet stay
localized for all times. Its fate in nonlinear disordered systems is under
intense theoretical debate and experimental study. We resolve this dispute
showing that at any small but finite nonlinearity (energy) value there is a
finite probability for Anderson localization to break up and propagating
nonlinear waves to take over. It increases with nonlinearity (energy) and
reaches unity at a certain threshold, determined by the initial wave packet
size. Moreover, the spreading probability stays finite also in the limit of
infinite packet size at fixed total energy. These results are generalized to
higher dimensions as well.Comment: 4 pages, 3 figure
- …