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