71 citations · 125 across the 6 of their papers we have counts for
5 papers · 1 filter
Quantum target detection using entangled photons
A. R. Usha Devi, A. K. Rajagopal
We investigate performances of pure continuous variable states in discriminating thermal and identity channels by comparing their M-copy error probability bounds. This offers us a…
Dynamical evolution of quantum oscillators towards equilibrium
A R Usha Devi, A K Rajagopal
A pure quantum state of large number N of oscillators, interacting via harmonic coupling, evolves such that any small subsystem n<<N of the global state approaches equilibrium. Thi…
Separability bounds on multiqubit moments due to positivity under partial transpose
A R Usha Devi, A K Rajagopal
Positivity of the density operator reflects itself in terms of sequences of inequalities on observable moments. Uncertainty relations for non-commuting observables form a subset of…
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…