Timeline of Quantum Computing - 1990s

1990s

• 1991 – Artur Ekert at the University of Oxford, invents entanglement based secure communication.

• 1993 – Dan Simon, at Université de Montréal, invented an oracle problem for which a quantum computer would be exponentially faster than conventional computer. This algorithm introduced the main ideas which were then developed in Peter Shor's factoring algorithm.

• 1994
  • Peter Shor, at AT&T's Bell Labs in New Jersey, discovers an important algorithm. It allowed a quantum computer to factor large integers quickly. It solved both the factoring problem and the discrete log problem. Shor's algorithm could theoretically break many of the cryptosystems in use today. Its invention sparked a tremendous interest in quantum computers.
  • First United States Government workshop on quantum computing is organized by NIST in Gaithersburg, Maryland, in autumn.
  • In December, Ignacio Cirac, at University of Castilla-La Mancha at Ciudad Real, and Peter Zoller at the University of Innsbruck proposed an experimental realization of the controlled-NOT gate with trapped ions.

• 1995
  • First United States Department of Defense workshop on quantum computing and quantum cryptography is organized by United States Army physicists Charles M. Bowden, Jonathan P. Dowling, and Henry O. Everitt; it takes place in February at the University of Arizona in Tucson.
  • Peter Shor and Andrew Steane simultaneously proposed the first schemes for quantum error correction. (An alternative to quantum error correction exploits special states that are immune to certain errors. This device is known as a decoherence-free subspaces.)
  • Christopher Monroe and David Wineland at NIST (Boulder, Colorado) experimentally realize the first quantum logic gate – the C-NOT gate – with trapped ions, according to Cirac and Zoller's proposal.

• 1996
  • Lov Grover, at Bell Labs, invented the quantum database search algorithm. The quadratic speedup is not as dramatic as the speedup for factoring, discrete logs, or physics simulations. However, the algorithm can be applied to a much wider variety of problems. Any problem that had to be solved by random, brute-force search, could now have a quadratic speedup.
  • The United States Government, particularly in a joint partnership of the Army Research Office (now part of the Army Research Laboratory) and the National Security Agency, issues the first public call for research proposals in quantum information processing.
  • David P. DiVincenzo, from IBM, proposed a list of minimal requirements for creating a quantum computer.

• 1997
  • David Cory, Amr Fahmy and Timothy Havel, and at the same time Neil Gershenfeld and Isaac L. Chuang at MIT published the first papers realising gates for quantum computers based on bulk spin resonance, or thermal ensembles. The technology is based on a nuclear magnetic resonance (NMR) machine, which is similar to the medical magnetic resonance imaging machine.
  • Alexei Kitaev described the principles of topological quantum computation as a method for combating decoherence.
  • Daniel Loss and David P. DiVincenzo proposed the Loss-DiVincenzo quantum computer, using as qubits the intrinsic spin-1/2 degree of freedom of individual electrons confined to quantum dots.

• 1998
  • First experimental demonstration of a quantum algorithm. A working 2-qubit NMR quantum computer used to solve Deutsch's problem was demonstrated by Jonathan A Jones and Michele Mosca at Oxford University and shortly after by Isaac L. Chuang at IBM's Almaden Research Center together with coworkers at Stanford University and MIT.
  • First working 3-qubit NMR computer.
  • First execution of Grover's algorithm on an NMR computer.

• 1999 – Samuel L. Braunstein and collaborators showed that there was no mixed state quantum entanglement in any bulk NMR experiment. Pure state quantum entanglement is necessary for any quantum computational speedup, and thus this gave evidence that NMR computers would not yield benefit over classical computer. It was still an open question as to whether mixed state entanglement is necessary for quantum computational speedup