5,001 research outputs found
Periodic variations in the colours of the classical T Tauri star RW Aur A
The classical T Tauri star RW Aur A is an irregular variable with a large
amplitude in all photometric bands. In an extended series of photometric data
we found small-amplitude periodic variations in the blue colours of the star,
with a period of 2.64 days. The period was relatively stable over several
years. The amplitude of the periodic signal is 0.21 mag in U-V, 0.07 mag in
B-V, and about 0.02 mag in V-R and V-I. No periodicity was found in the V
magnitude. The relevance of this photometric period to the recently discovered
periodicity in spectral features of the star is discussed, and the hypothesis
of a hot spot is critically considered.Comment: 5 pages, 8 figures, uses new aa.cls, accepted for publication in
Astronomy and Astrophysic
Confinement and Chiral Symmetry
We illustrate why color deconfines when chiral symmetry is restored in gauge
theories with quarks in the fundamental representation, and while these
transitions do not need to coincide when quarks are in the adjoint
representation, entanglement between them is still present.Comment: 4 pages, 1 figure, proceedings of Quark Matter 200
Measurement of Magnetization Dynamics in Single-Molecule Magnets Induced by Pulsed Millimeter-Wave Radiation
We describe an experiment aimed at measuring the spin dynamics of the Fe8
single-molecule magnet in the presence of pulsed microwave radiation. In
earlier work, heating was observed after a 0.2-ms pulse of intense radiation,
indicating that the spin system and the lattice were out of thermal equilibrium
at millisecond time scale [Bal et al., Europhys. Lett. 71, 110 (2005)]. In the
current work, an inductive pick-up loop is used to probe the photon-induced
magnetization dynamics between only two levels of the spin system at much
shorter time scales (from ns to us). The relaxation time for the magnetization,
induced by a pulse of radiation, is found to be on the order of 10 us.Comment: 3 RevTeX pages, including 3 eps figures. The paper will appear in the
Journal of Applied Physics as MMM'05 conference proceeding
Decoherence in circuits of small Josephson junctions
We discuss dephasing by the dissipative electromagnetic environment and by
measurement in circuits consisting of small Josephson junctions. We present
quantitative estimates and determine in which case the circuit might qualify as
a quantum bit. Specifically, we analyse a three junction Cooper pair pump and
propose a measurement to determine the decoherence time .Comment: 4 pages, 4 figure
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