---
title: "Quantum computing · Library · Simulation Hypothesis"
url: https://simulation-hypothesis.com/library/quantum-computing
description: "Quantum computing uses superposition and entanglement."
license: https://creativecommons.org/licenses/by/4.0/
credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)"
---

## Physics & computation

# Quantum computing

Definition

Quantum computing uses superposition and entanglement. Richard Feynman (1982) pointed out that ordinary computers can’t efficiently simulate typical quantum systems, and proposed quantum computers as the fix.

On this site

The Quantum, fully entangled rung is worked out for an ordinary classical machine, which has to store 2^(particles) amplitudes. This is the obstacle Feynman described.

Role in the model

Feynman’s point was that a classical computer needs 2^N numbers to describe N entangled particles. The Quantum, fully entangled rung is that number for a whole universe. It’s the one setting that pushes the total off the scale, because the exponent itself needs an exponent.

Related

[Superposition](https://simulation-hypothesis.com/library/superposition)[Entanglement](https://simulation-hypothesis.com/library/entanglement)[Lattice QCD](https://simulation-hypothesis.com/library/lattice-qcd)

In the trees

[Feynman’s quantum simulator · Simulations](https://simulation-hypothesis.com/trees/simulations?n=mat-feynman)[Quantum chemistry simulation · Simulations](https://simulation-hypothesis.com/trees/simulations?n=f-quantum)

## The people behind the terms

14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading).

[Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers)