[[Quantum Decoherence]] The essence of the idea is that if we want to protect a complex quantum system we should encode it in a very non-local form, shared among many qubits. So the environment which typically interacts locally will look at the parts one at a time, but by doing that it won't be able to gain any information about that non-locally encoded state. ![[Pasted image 20211116105936.png]] https://journals.aps.org/prxquantum/pdf/10.1103/PRXQuantum.2.040335 Quantum Error Correction carries a high overhead cost in number of qubits and gates. This cost depends on both the hardware quality and algorithm complexity. #toWrite Best sources: