arXiv subjects
Publications and source records attributed to Saikat Patra.
Heisenberg-Weyl operators provide a Hermitian generalization of Pauli operators in higher dimensions. Positive maps arising from Heisenberg-Weyl operators have been studied along with several algebraic and spectral properties of Heisenberg-Weyl observables. This allows to generalize the study of Pauli type maps in higher dimesional algebra of operators.
In recent years, the activation of hidden nonlocality for a mixed entangled state, admitting a local model, has gained considerable interest. In this paper, we study the activation of hidden nonlocality and preparation contextuality for a class of mixed entangled states, using local filtering operations. For our demonstration, we consider the two-party (Alice and Bob) one-way communication game known as parity oblivious random access code (PORAC). The quantum success probability of such $n$-bit PORAC solely depends on a Bell functional involving $2^{n-1}$ and $n$ dichotomic measurement settings for Alice and Bob, respectively. Such a Bell functional has two classical bounds, the local and the preparation non-contextual. We show that using local filtering operations on local mixed entangled state, the nonlocality can be revealed for any non-zero value of the mixedness parameter of the entangled state if $n\geq6$. Further, we show that the preparation contextuality, which is a comparatively weaker quantum correlation than nonlocality, can be revealed for any non-zero value of the mixedness parameter of the entangled state if $n\geq 4$.
Completely positive trace preserving maps are widely used in quantum information theory. These are mostly studied using the master equation perspective. A central part in this theory is to study whether a given system of dynamical maps $\{\Lambda_t: t \ge 0\}$ is Markovian or non-Markovian. We study the problem when the underlying Hilbert space is of infinite dimensional. We construct a sufficient condition for checking P (resp. CP) divisibility of dynamical maps. We construct several examples where the underlying Hilbert space may not be of finite dimensional. We also give a special emphasis on Gaussian dynamical maps and get a version of our result in it.
We have found conic programs for getting different types of quantum channels as outputs of interpolation problems. Afterwards, we have generalized our results for getting channels that belong to a convex set as outputs of the interpolation problem. We show the existence of an Entanglement breaking channel for orthogonal sets of input and output matrices.