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3 sats \ 0 replies \ @south_korea_ln 5 Jul \ on: Multiple nations enact mysterious export controls on quantum computers tech
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.
34 seems quite conservative. There have been systems proposed going beyond 100 qubits if I recall well. Although one should never trust claims made by Google, IBM, etc on quantum supremacy. Scientists working in the field without financial incentives claim we haven't reached it yet.
34 qubits would correspond to about 256 GB in terms of memory. Nothing too fancy. However, in terms of computation speed, this is already exponentially faster than classical algorithms. Say compare Quantum Fourier Transform used in Shor's algorithmm going at O(n^2) and Fast Fourier Transform taking O(2^n log 2^n)... you can immediately see that the n is in the wrong position in the latter case when compared to the former scaling.
34 qubits, things start to get interesting. But to break RSA encryption, we'd need 1000s of qubits.
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