Quantum Processors

Dreams of quantum computers has been around for decades. In the 1980s, Richard Feynman showed that a classical Turing machine will encounter an exponential slowdown in processing power, both in speed and memory, if it is used for simulating quantum phenomena. What about a quantum calculating machine? The idea of a quantum computer was born. Within a few years, researchers had shown that a working quantum computer could perform certain tasks, such as data base search (by Grover's algorithm) and factorization (with Shor's algorithm), much faster than would be possible on a classical machine.

Research on how to actually build and operate a quantum computer continues. Implementing quantum algorithms on physical platforms is a non-trivial task. Atoms, photons, ions, electrons and numerous other microscopic systems have all been proposed as quantum bits (qubits). Complicated control mechanisms involving lasers and magnetic fields to implement the basic quantum gates have been considered. However, a scalable quantum architecture that can maintain the entanglement between qubits needed for computation is yet to be proven.

Quantum processor research in CQT spans quantum optical and condensed matter systems and hybrids of these. For example, we work on how to efficiently implement quantum algorithms like Grover's, how to create long-lived entanglement in realistic dissipation conditions and how to simulate complex quantum phenomena in simple optical set ups (in the group page of Dimitris G. Angelakis). Kwek Leong Chuan's group is examining the possibilities of performing quantum computing tasks without having to get physical qubits interacting. Instead the qubits are kept at well separated sites and simply subjected to measurement. This paradigm of distributed QIP is increasingly perceived as an excellent prospect for a real, practical technology.

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