Quantum computation utilizes quantum mechanical effects such as superposition, entanglement, and interference to perform computation. Classical computation relies on the ability to store and manipulate binary integers (bits) generally made from silicon transistors. Instead quantum computers make use of quantum bits (qubits) that can have the value 0, 1 or a superposition of these 2 states. Leveraging superposition and entanglement to create states that scale exponentially with the number of qubits offers the potential for dramatic improvements in computation power compared to classical computers.

A quantum mechanical model of a computer was first conceived by physicist Paul Benioff in 1980, inspired by an Alan Turing paper written in 1936. These ideas were developed by David Deutsch in 1985, describing the concept of a universal quantum computer to understand the mathematical potential that was possible. In 1994 Peter Shor developed “Shor’s algorithm” allowing a quantum computer to perform factorization of large numbers significantly faster than the best classical algorithms.

Development continued through the 90s and 2000s with significant contributions from scientists David Wineland, Christopher Monroe, and Lov Grover, companies and institutions such as the Technical University of Munich, Los Alamos National Laboratory, IBM, D-Wave, and Google. On October 23rd, 2019 researchers at Google published a paper claiming they had achieved quantum supremacy using the Sycamore quantum computer. Quantum supremacy refers to solving a problem that could not be solved by a classical computer in a reasonable amount of time. Although some disagreed whether Google had achieved true quantum supremacy it is seen as a significant breakthrough in quantum computation.

Current quantum computers struggle with errors in the form of noise and loss of quantum coherence as well as engineering challenges. However, they have found applications in fields such as cryptography and drug development.

## Fundamental Science

### Quantum Mechanics

### Qubits

### Quantum Algorithms

### Related Topics

- Quantum machine learning
- Quantum Memory
- Quantum information
- Quantum photonics
- Integrated quantum photonics

## Applications

### Quantum simulation

Quantum computing is bringing forth the opportunity to run virtual simulations instead of physically conducting experiments in a laboratory in areas such as drug discovery, material production and manufacturing, finance and traffic analysis.

## Quantum Computing Companies

List of companies that are developing both hardware and software for quantum computation:

- Atom Computing
- Honeywell
- IBM
- Intel
- Microsoft
- Toshiba
- Nordic Quantum Computing Group (NQCG)
- Optalysys
- TundraSystems Global
- Cambridge Quantum Computing
- Oxford Quantum Circuits
- Alpine Quantum Technologies
- Quantum Factory
- 1QBit
- Quandela
- Agnostiq
- ColdQuanta

### Quantum computing hardware

- IonQ
- IQM
- QuiX
- Bleximo Corp
- Anyon Systems
- Silicon Quantum Computing
- Quantum Circuits
- Quantum Motion
- PsiQuantum
- ORCA Computing
- Pasqal

### Quantum computing software

- Entropica Labs
- GTN Ltd
- ApexQubit
- AppliedQubit
- Q-CTRL
- ISARA
- Quantum Benchmark
- Rahko
- Zapata Computing
- Aliro Quantum
- PhaseCraft
- artiste-qb.net
- Riverlane
- Elyah
- Strangeworks
- QxBranch
- QC Ware

### Other quantum computing companies

## Notable quantum computers

## Timeline

## People

Hartmut Neven

Creator Neven's Law

## Further reading

Neven's Law

James Dargan

Web

July 1, 2019

## Documentaries, videos and podcasts

## Companies

Trapped-ion qubits