Quantum tomography of entangled qubits by time-resolved single-photon counting with time-continuous measurements

Abstract

In this article, we introduce a framework for entanglement characterization by time-resolved single-photon counting with measurement operators defined in the time domain. For a quantum system with unitary dynamics, we generate time-continuous measurements by shifting from the Schrödinger picture to the Heisenberg representation. In particular, we discuss this approach in reference to photonic tomography. To make the measurement scheme realistic, we impose timing uncertainty on photon counts along with the Poisson noise. Then, the framework is tested numerically on quantum tomography of qubits. Next, we investigate the accuracy of the model for polarization-entangled photon pairs. Entanglement detection and precision of state reconstruction are quantified by figures of merit and presented on graphs versus the amount of time uncertainty.

Extremal quantum correlation generation using a hybrid channel

“…In quantum information processing, nearly all the quantum phenomena and related efficiency are based on the degree of non-classical correlations between the sub-systems of a composite state 23 . For instance, quantum mechanical protocols such as quantum imaging 24 , teleportation 25 , metrology 26 , remote state preparation 27 , key-distribution 28 , cryptography 29 , and quantum state tomography 30 , 31 are few to name. In this regard, various schemes for quantum correlation generation have been proposed theoretically and experimentally.…”

Quantum teleportation in a two-superconducting qubit system under dephasing noisy channel: role of Josephson and mutual coupling energies

“…Because of the decoherence effects, an entangled state may become mixed when combined with the external environment in a teleportation scheme * Author to whom any correspondence should be addressed. [4][5][6][7][8][9][10][11]. One of the core quantum information protocols proposed in references [12,13] is quantum teleportation, which allows us to send an unknown non-classical state over a long distance using shared entanglement and local communication.…”