50 citations · 136 across the 28 of their papers we have counts for
16 papers · 1 filter
POVM generated quantum trajectories without stochastic differential equations
Rutvij Bhavsar, N. D. Hari Dass
In this paper we examine the issue of quantum trajectories generated by QND-POVM's on {\it single} copies of unknown states. After an introduction to various aspects of quantum mea…
Optimal weak measurements: Mixed States
N. D. Hari Dass, R. Rajath Krishna
In an earlier publication we had given an exhaustive analysis of the criteria for weak value measurements of pure states to be optimal in the sense considered by Wootters and Field…
Optimal weak value measurements: Pure states
N. D. Hari Dass, R. Rajath Krishna, Sai Smruti Samantaray
We apply the notion of \emph{optimality} of measurements for state determination(tomography) as originally given by Wootters and Fields to \emph{weak value tomography} of \emph{pur…
Bell-like examples for spin-1 hidden variable theories
Kaushik Borah, N. D. Hari Dass
Though John Bell had claimed that his spin-1/2 example of a hidden-variable theory(HV) is an \emph{explicit} counterexample to von Neumann's proof of the non-existence of hidden va…
Three results on weak measurements
N. D. Hari Dass
Three recent results on weak measurements are presented. They are: i) repeated measurements on a single copy can not provide any information on it and further, that in the limit of…
Protective Measurements: Probing Single Quantum Systems
Tabish Qureshi, N. D. Hari Dass
Making measurements on single quantum systems is considered difficult, almost impossible if the state is a-priori unknown. Protective measurements suggest a possibility to measure…
On repeated (continuous) weak measurements of a single copy of an unknown quantum state
N. D. Hari Dass
In this paper we investigate repeated weak measurements,without post-selection, on a \emph{single copy} of an \emph{unknown} quantum state. The resulting random walk in state space…
Unknown single oscillator coherent states do have statistical significance
N. D. Hari Dass
It is shown, contrary to popular belief, that {\it single unknown} oscillator coherent states can be endowed with a {\em measurable statistical significance}.
An alternate model for protective measurements of two-level systems
Anirban Das, N. D. Hari Dass
In this article we propose an alternate model for the so called {\it protective measurements}, more appropriately {\it adiabatic measurements} of a spin 1/2 system where the {\it a…
Purifications Without Entanglement, State Reconstructions and Entropy
Chirag Dhara, N. D. Hari Dass
In this paper we have analysed in detail two different purification protocols. The first one, proposed by Sudarshan, is based on the preservation of probabilities.We have construct…
Purification of Single Qubits and reconstruction from Post-Measurement State
Chirag Dhara, N. D. Hari Dass
Purification of mixed states in Quantum Mechanics, by which we mean the transformation into pure states, has been viewed as an {\it Operation} in the sense of Kraus et al and expli…
A New Relation between post and pre-optimal measurement states
Chirag Dhara, N. D. Hari Dass
When an optimal measurement is made on a qubit and what we call an Unbiased Mixture of the resulting ensembles is taken, then the post measurement density matrix is shown to be rel…
Information cloning of harmonic oscillator coherent states and its fidelity
N. D. Hari Dass, Pradeep Ganesh
We show that in the case of unknown {\em harmonic oscillator coherent states} it is possible to achieve what we call {\it perfect information cloning}. By this we mean that it is s…
Perfect cloning of harmonic oscillator coherent states is possible
N. D. Hari Dass, Pradeep Ganesh
We have withdrawn this paper due to a fatal flaw in eqn(38).
Cold Atoms For Testing Quantum Mechanics and Parity Violation In Gravitation
N. D. Hari Dass
Techniques of Atom trapping and laser cooling have proved to be very important tools in probing many aspects of fundamental physics. In this talk I wish to present ideas on how the…
Critique of Protective Measurements
N. D. Hari Dass, Tabish Qureshi
Recently proposed idea of "protective" measurement of a quantum state is critically examined, and generalized. Earlier criticisms of the idea are discussed and their relevance to t…