An electrons and holes of indirect excitons in semiconductor coupled quantum wells are localized in different wells and as the result the excitons have long lifetime. Such system present interest for study of exciton condensation phenomena [1]. Recently interesting experiments were fulfilled for indirect excitons in AlGaAs and InGaAs crystals with coupled quantum wells. In works [2, 3, 4, 5, 6,...

Speedmeters are known to be quantum non-demolition devices and, by potentially providing sensitivity beyond the standard quantum limit, become interesting for third generation gravitational wave detectors. Here we introduce a new configuration, the sloshing-Sagnac interferometer, and compare it to the more established ring-Sagnac interferometer. The sloshing-Sagnac interferometer is designed to...

Speedmeters are known to be quantum non-demolition devices and, by potentially providing sensitivity beyond the standard quantum limit, become interesting for third generation gravitational wave detectors. Here we introduce a new configuration, the sloshing-Sagnac interferometer, and compare it to the more established ring-Sagnac interferometer. The sloshing-Sagnac interferometer is designed to...

Motivated by the quantum algorithm for testing commutativity of black-box groups (Magniez and Nayak, 2007), we study the following problem: Given a black-box finite ring by an additive generating set and a multilinear polynomial over that ring, also accessed as a black-box function (we allow the indeterminates of the polynomial to be commuting or noncommuting), we study the problem of testing i...

These results stem from a course on ring theory. Quantum planes are rings in two variables x and y such that yx = qxy where q is a nonzero constant. When q = 1 a quantum plane is simply a commutative polynomial ring in two variables. Otherwise a quantum plane is a noncommutative ring. Our main interest is in quadratic forms belonging to a quantum plane. We provide necessary and sufficient condi...