Exciton condensates in semiconductor quantum wells emit coherent light

We show that a quasi-two dimensional condensate of optically active excitons emits coherent light even in the absence of population inversion. This allows an unambiguous and clear experimental detection of the condensed phase. We prove that, due to the exciton-photon coupling, quantum and thermal fluctuations do not destroy condensation at finite temperature. Suitable conditions to achieve condensation are temperatures of a few K for typical exciton densities, and the use of a pulsed, and preferably circularly polarized, laser.Comment: 5 pages, no figure

Modelling of Optical Detection of Spin-Polarized Carrier Injection into Light-Emitting Devices

We investigate the emission of multimodal polarized light from Light Emitting Devices due to spin-aligned carriers injection. The results are derived through operator Langevin equations, which include thermal and carrier-injection fluctuations, as well as non-radiative recombination and electronic g-factor temperature dependence. We study the dynamics of the optoelectronic processes and show how the temperature-dependent g-factor and magnetic field affect the polarization degree of the emitted light. In addition, at high temperatures, thermal fluctuation reduces the efficiency of the optoelectronic detection method for measuring spin-polarization degree of carrier injection into non-magnetic semicondutors.Comment: 15 pages, 7 figures, replaced by revised version. To appear in Phys. Rev.

Patent ductus arteriosus repair

A 4-month-old, intact female, Border Collie Presented to Cornell’s Cardiology service on 11/7/12 after her referring veterinarian diagnosed a murmur at an initial puppy exam. She was an otherwise healthy puppy with no exercise intolerance and a good energy level. An echocardiogram was performed that revealed a patent ductus arteriosus (PDA) with left to right flow. This seminar will provide a review of the case; discuss the pathology of a PDA, treatment options and prognosis for this patient