Articles written in Pramana – Journal of Physics
Volume 28 Issue 4 April 1987 pp 1-
A manifestly covariant Lagrangian is presented which leads to the reformulation of canonical general relativity using new variables recently discovered by Ashtekar.
Volume 47 Issue 5 November 1996 pp 361-369
We point out that the Poincaré sphere can be used to represent the rays of a three state quantum system. Those interested in geometric phase phenomena may find this representation a useful aid to visualize the global structure of ray space.
Volume 48 Issue 5 May 1997 pp 959-967
We study the behaviour of the geometric phase under isometries of the ray space. This leads to a better understanding of a theorem first proved by Wigner: isometries of the ray space can always be realised as projections of unitary or anti-unitary transformations on the Hilbert space. We suggest that the construction involved in Wigner’s proof is best viewed as an use of the Pancharatnam connection to ‘lift’ a ray space isometry to the Hilbert space.
Volume 48 Issue 5 May 1997 pp 969-975
We describe a
Volume 94 All articles Published: 15 March 2020 Article ID 0057 Rapid communication
By repeated trials, one can determine the fairness of a classical coin with a confidence which grows with the number of trials. A quantum coin can be in a superposition of heads and tails and its state is most generally a density matrix. Given a string of qubits representing a series of trials, one can measure them individually and determine the state with a certain confidence.We show that there is an improved strategy which measures the qubits after entangling them, which leads to a greater confidence. This strategy is demonstrated on the simulation facility of IBM quantum computers.
Volume 96, 2022
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