ON THE second day of the six-day international conference on ‘Quantum Computing: Back Action’ at the Indian Institute of Technology (IIT-K) here on Tuesday, five eminent scientists spoke on futuristic technology.
Seth Lloyd from USA said that every atom and elementary particle in the universe had with it bits of information. Every time two elementary particles collided, those bits were flipped and processed and the universe computed.
“This leads us to make efforts as how we can hack into the universe’s computation to construct quantum computers, devices that store and process information at the level of elementary particles,” he said.
Jason Taylor and Neil Gershenfeld from The Centre for Bits and Atoms, MIT, USA, said ultrafast lasers had applications in quantum computing. He presented preliminary experiments and supporting modeling in both these directions.
Sougato Bose from Centre for Quantum Computation, Clarendon Laboratory Oxford, United Kingdom, presented a general scheme in which a single qubit was coupled to a mesoscopic harmonic oscillator in such a way that it could be used to both prepare and probe a superposition of states of the oscillator. Two potentially realizable implementations, one with a single flux qubit coupled to a LC circuit, and the other with a single ion-trap qubit coupled to the collective motion of several ions, were proposed. He also presented a dualism in the entanglement of identical particles.
Given prior entanglement of two identical objects, this dualism enables a universal test of quantum indistinguishability in the sense that it was unaffected by the mutual interactions of the particles involved. This was in contrast to existing tests, which were expected to be affected by mutual interactions, he said.
{{/usCountry}}Given prior entanglement of two identical objects, this dualism enables a universal test of quantum indistinguishability in the sense that it was unaffected by the mutual interactions of the particles involved. This was in contrast to existing tests, which were expected to be affected by mutual interactions, he said.
{{/usCountry}}Subhash Chaturvedi from the physics department, University of Hyderabad, presented a fresh approach to Wigner distribution for finite state quantum systems. The formalism was inspired by Dirac’s work on functions of non-commuting observables and entails taking the square root, in a suitable fashion, of a certain kernel which appeared in expression for the trace of product of two operators.
GS Agarwal from the department of physics at Oklahoma State University, discussed ways to generate entanglement between variety of systems, including the mesoscopic ones. He discussed various ideas from cavity QED and the collective dynamics of atoms and showed how quantum entanglement in a collective system developed in time and how the entanglement could be transferred from one system to another.
Martin B Plenio from QOLS, Blackett Laboratory, Imperial College, London, said in the early years one focus of attention in quantum information science was the study of entanglement between two parties. A reasonably detailed understanding was reached. The same could not be said, however, about the detailed study of entanglement between three or more parties. One of the reasons is the rapid increase in different classes of entanglement in the setting.
In recent years, the emphasis has, therefore, shifted towards the investigation of general features of entanglement in quantum. He presented some of the results that were obtained in this direction.