Noisy intermediate-scale quantum era
In the noisy intermediate-scale quantum (NISQ) era[1] the leading quantum processors contain about 50 to a few hundred qubits, but are not advanced enough to reach fault-tolerance nor large enough to profit sustainably from quantum supremacy.[2][3] The term was coined by John Preskill in 2018.[4][1] It is used to describe the current state of the art in the fabrication of quantum processors.[5]
The term 'noisy' refers to the fact that quantum processors are very sensitive to the environment and may lose their quantum state due to quantum decoherence. In the NISQ era, the quantum processors are not sophisticated enough to continuously implement quantum error correction. The term 'intermediate-scale' refers to the quantum volume related to the not-so-large number of qubits and moderate gate fidelity.
Algorithms[]
The term NISQ algorithms refers to algorithms designed for quantum processors in the NISQ era. For example, the variational quantum eigensolver (VQE) or the quantum approximate optimization algorithm (QAOA), are hybrid algorithms that use NISQ devices but reduce the calculation load by implementing some parts of the algorithm in usual classical processors.[1] These algorithms have been proven to recover known results in quantum chemistry and some applications have been suggested in physics, material science, data science, cryptography, biology and finance.[1][6][3]
Usually, NISQ algorithms require error mitigation techniques to recover useful data.[7]
Beyond-NISQ era[]
The creation of a computer with tens of thousands of qubits and enough error correction would eventually end the NISQ era.[2] These beyond NISQ devices would be able, for example, to implement Shor's algorithm, for very large numbers and break RSA encryption.[8]
References[]
- ^ a b c d Brooks, Michael (2019-10-03). "Beyond quantum supremacy: the hunt for useful quantum computers". Nature. 574 (7776): 19–21. doi:10.1038/d41586-019-02936-3. ISSN 0028-0836.
- ^ a b "Engineers demonstrate a quantum advantage". ScienceDaily. Retrieved 2021-06-29.
- ^ a b "What is Quantum Computing?". TechSpot. Retrieved 2021-06-29.
- ^ Preskill, John (2018-08-06). "Quantum Computing in the NISQ era and beyond". Quantum. 2: 79. doi:10.22331/q-2018-08-06-79.
- ^ "Quantum Computing Scientists: Give Them Lemons, They'll Make Lemonade". www.aps.org. Retrieved 2021-06-29.
- ^ "Quantum computers are already detangling nature's mysteries". Wired UK. ISSN 1357-0978. Retrieved 2021-06-29.
- ^ Ritter, Mark B. (2019). "Near-term Quantum Algorithms for Quantum Many-body Systems". Journal of Physics: Conference Series. 1290: 012003. doi:10.1088/1742-6596/1290/1/012003. ISSN 1742-6588.
- ^ O'Gorman, Joe; Campbell, Earl T. (2017-03-31). "Quantum computation with realistic magic-state factories". Physical Review A. 95 (3): 032338. doi:10.1103/PhysRevA.95.032338. ISSN 2469-9926.
External links[]
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