arXiv subjects

P K Pathak

Publications and source records attributed to P K Pathak.

3 recordsLinked to original sources

arXiv2016

Highly efficient two photon generation from a coherently pumped quantum dot embedded in a microcavity

We propose a scheme to realize a highly efficient solid state source of photon pairs using cavity-assisted stimulated Raman adiabatic passage (STIRAP) in a single quantum dot, where a single photon from pump pulse and two stokes photons from cavity mode drives the Raman transition. The Autler-Townes doublet, generated by using a resonant continuous wave laser between biexciton and exciton states, and two-photon-resonant transition through strongly coupled cavity mode are utilized to facilitate (1+2)type Raman transition in the quantum dot. We show in the case of weak pump although the probability of generating two photons in cavity mode is small without cavity damping but two-photon-resonant emission is enhanced by cavity damping within strong coupling regime. We also discuss spectrum of the generated photon pair and photon-photon correlations in the generated photon pair. The efficiency of two photon source could be more than 80\% in current experimental conditions.

cond-mat.mes-hall↗

arXiv2006

Realization of quantum mechanical weak values of observables using entangled photons

We present a scheme for realization of quantum mechanical weak values of observables using entangled photons produced in parametric down conversion. We consider the case when the signal and idler modes are respectively in a coherent state and vacuum. We use a low efficiency detector to detect the photons in the idler mode.This weak detection leads to a large displacement and fluctuations in the signal field's quantum state which can be studied by monitoring the photon number and quadrature distributions.

quant-ph↗

arXiv2005

Quantum random walk of the field in an externally driven cavity

Using resonant interaction between atoms and the field in a high quality cavity, we show how to realize quantum random walks as proposed by Aharonov et al [Phys. Rev. A {\bf48}, 1687 (1993)]. The atoms are driven strongly by a classical field. Under conditions of strong driving we could realize an effective interaction of the form $ iS^{x}(a-a^†)$ in terms of the spin operator associated with the two level atom and the field operators. This effective interaction generates displacement in the field's wavefunction depending on the state of the two level atom. Measurements of the state of the two level atom would then generate effective state of the field. Using a homodyne technique, the state of the quantum random walker can be monitored.

quant-ph↗