4,708 research outputs found
Spontaneous two photon emission from a single quantum dot
Spontaneous two photon emission from a solid-state single quantum emitter is
observed. We investigated photoluminescence from the neutral biexciton in a
single semiconductor quantum dot coupled with a high Q photonic crystal
nanocavity. When the cavity is resonant to the half energy of the biexciton,
the strong vacuum field in the cavity inspires the biexciton to simultaneously
emit two photons into the mode, resulting in clear emission enhancement of the
mode. Meanwhile, suppression was observed of other single photon emission from
the biexciton, as the two photon emission process becomes faster than the
others at the resonance.Comment: 13 pages, 4 figure
LHC Benchmarks from Flavored Gauge Mediation
We present benchmark points for LHC searches from flavored gauge mediation
models, in which messenger-matter couplings give flavor-dependent squark
masses. Our examples include spectra in which a single squark - stop, scharm,
or sup - is much lighter than all other colored superpartners, motivating
improved quark flavor tagging at the LHC. Many examples feature flavor mixing;
in particular, large stop-scharm mixing is possible. The correct Higgs mass is
obtained in some examples by virtue of the large stop A-term. We also revisit
the general flavor and CP structure of the models. Even though the A-terms can
be substantial, their contributions to EDM's are very suppressed, because of
the particular dependence of the A-terms on the messenger coupling. This holds
regardless of the messenger-coupling texture. More generally, the special
structure of the soft terms often leads to stronger suppression of flavor- and
CP-violating processes, compared to naive estimates.Comment: 32 pages, 11 figures. Updated to published versio
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