Edge-state Fabry-Perot interferometer as a high-sensitivity charge detector

Abstract

We present a scheme for high sensitivity charge detection in the integer quantum Hall regime using two point contacts in a series. The setup is an electronic analog of an optical Fabry-Perot interferometer. We show that for small transmission through the point contacts the sensitivity of the interferometer is very high due to multiple reflections at the point contacts. The sensitivity can be further enhanced twice by using electrons in spin entangled state. We show that for point contacts having different reflection probabilities, the interferometer can be tuned for the quantum limited measurement.

Two-photon lasing by a single quantum dot in a high-Qmicrocavity

“…1(b)). Previous theoretical works used this level scheme in order to study the emission of polarizationentangled photon pairs from a single quantum dot [30][31][32][33][34] . In the present paper, we consider a setup where the same cavity mode couples with the biexciton-exciton and exciton-ground state transitions, setting hence the basic requirements for the emission of two photons into the same mode of the electromagnetic field.…”

Efficient Generation of Entangled Photon Pairs from a Single Quantum Dot Embedded in a Photonic Crystal Cavity

“…In their scheme, excitons are strongly coupled with cavity modes and form degenerate polariton states 25 . A formal theory of this scheme, including exciton and biexciton broadenings, has been reported by us 26 . However, one drawback of the proposed scheme is that because of the large binding energy, the biexciton remains uncoupled with cavity modes and thus the first generation of photons has a long life time.…”

“…For within generation of entangled photons, the x−polarized and y−polarized photons should match in energy within the same generations. In this case we consider the exciton states, which have a small but nonzero FSS, to interact with cavity modes in strong coupling regime so that the system forms degenerate polariton states 24,26 . Here we extend previous works 24,26 by considering that the biexciton state is also coupled with the same cavity modes by reducing the binding energy; however, the biexciton to exciton transition is more offresonant so that further splitting in the polariton states due to biexciton couplings is negligible.…”

Polarization-entangled photon generation in a semiconductor quantum dot coupled to a cavity interacting with external fields

“…This is achieved, as the dressed-states formed in the SQD-cavity system eliminate the which-path information which prevents the formation of entangled-photon pair in the biexciton decay process. Moreover, the energies of these intermediate dressed states are tuned to be degenerate states by using a high-Q cavity [20,21,22].…”