The UK is one of the countries that has prohibited the export of quantum computers with 34 or more quantum bits, or qubits, and error rates below a certain threshold. The intention seems to be to restrict machines of a certain capability, but the UK government hasn’t explicitly said this. A New Scientist freedom of information request for a rationale behind these numbers was turned down on the grounds of national security. France has also introduced export controls with the same specifications on qubit numbers and error rates, as has Spain and the Netherlands. Identical limits across European states might point to a European Union regulation, but that isn’t the case. A European Commission spokesperson told New Scientist that EU members are free to adopt national measures, rather than bloc-wide ones, for export restrictions.
New Scientist reached out to dozens of nations to ask what the scientific basis for these matching legislative bans on quantum computer exports was, but was told it was kept secret to protect national security.