71 citations · 111 across the 3 of their papers we have counts for
5 papers · 1 filter
A scheme for amplification and discrimination of photons
A. R. Usha Devi, R. Prabhu, A. K. Rajagopal
A scheme for exploring photon number amplification and discrimination is presented based on the interaction of a large number of two-level atoms with a single mode radiation field.…
Characterizing multiparticle entanglement in symmetric N-qubit states via negativity of covariance matrices
A. R. Usha Devi, R. Prabhu, A. K. Rajagopal
We show that higher order inter-group covariances involving even number of qubits are necessarily positive semidefinite for N qubit separable states, which are completely symmetric…
Non-classicality of photon added coherent and thermal radiations
A. R. Usha Devi, R. Prabhu, M. S. Uma
Production and analysis of non-Gaussian radiation fields has evinced a lot of attention recently. Simplest way of generating such non-Gaussians is through adding (subtracting) phot…
Constraints on the uncertainties of entangled symmetric qubits
A. R. Usha Devi, M. S. Uma, R. Prabhu +1
We derive necessary and sufficient inseparability conditions imposed on the variance matrix of symmetric qubits. These constraints are identified by examining a structural parallel…
Non-local properties of a symmetric two-qubit system
A. R. Usha Devi, M. S. Uma, R. Prabhu +1
Non-local properties of symmetric two-qubit states are quantified in terms of a complete set of entanglement invariants. We prove that negative values of some of the invariants are…