Quantum data processing system

1. A computer implemented method comprising:

storing, in a quantum memory, multiple copies of a quantum state, comprising, for each copy of the quantum state, i) probing, by an initialized quantum sensor, a target system to obtain an evolved quantum state of the quantum sensor, ii) transducing the evolved quantum state of the quantum sensor into a quantum state of a quantum buffer, iii) logically encoding the quantum state of the quantum buffer into a quantum error correcting code, and iv) moving the logically encoded quantum state of the quantum buffer into the quantum memory;

loading the multiple copies of the quantum state in the quantum memory into a quantum computer;

processing, by the quantum computer, the multiple copies of the quantum state to obtain a purified quantum state; and

measuring the purified quantum state to determine properties of the target system.

2. The method of claim 1 , wherein the quantum sensor is configured to maintain quantum coherence.

3. The method of claim 1 , wherein the evolved quantum state of the quantum sensor encodes properties of the target system at the time of the probing.

4. The method of claim 1 , wherein the evolved quantum state of the quantum sensor comprises a state of multiple qubits or a state of bosonic or photonic modes.

5. The method of claim 1 , wherein probing the target system to obtain the evolved quantum state of the quantum sensor is performed with finite signal to noise ratio.

6. The method of claim 1 , wherein the quantum sensor is configured to implement full or partial quantum error correction on the evolved quantum state of the quantum sensor.

7. The method of claim 1 , wherein the quantum sensor comprises a first computational medium and the quantum buffer comprises a second computational medium, wherein the second computational medium is different to the first computational medium.

8. The method of claim 1 , wherein logically encoding the quantum state of the quantum buffer into a quantum error correcting code comprises applying a unitary encoding quantum circuit to the quantum state of the quantum buffer or performing a state injection technique.

9. The method of claim 1 , wherein the quantum error correcting code comprises a code distance that is dependent on at least one of: operations performed by the quantum computer to obtain the purified quantum state or an expected duration required to store the multiple copies of the quantum state.

10. The method of claim 1 , wherein the quantum error correcting code is the quantum buffer.

11. The method of claim 1 , wherein processing the multiple copies of the quantum state to obtain a purified quantum state comprises performing a linear distillation technique to purify the multiple copies of the quantum state.

12. The method of claim 11 , wherein the linear distillation technique comprises quantum state distillation, virtual state distillation or a quantum principle component analysis algorithm.

13. The method of claim 1 , wherein measuring the purified quantum state to determine properties of the target system comprises providing measurement results to a quantum machine learning system to learn the properties of the target system.

14. The method of claim 1 , wherein the target system comprises a transient target system.

15. A quantum data processing system comprising a quantum sensor, a quantum buffer, a quantum memory, and a quantum computing device, wherein the quantum data processing system is configured to perform operations comprising:

storing, in the quantum memory, multiple copies of a quantum state, comprising, for each copy of the quantum state, i) probing, by the quantum sensor, a target system to obtain an evolved quantum state of the quantum sensor, ii) transducing the evolved quantum state of the quantum sensor into a quantum state of the quantum buffer, iii) logically encoding the quantum state of the quantum buffer into a quantum error correcting code, and iv) moving the logically encoded quantum state of the quantum buffer into the quantum memory;

loading the multiple copies of the quantum state in the quantum memory into the quantum computer;

processing, by the quantum computer, the multiple copies of the quantum state to obtain a purified quantum state; and

measuring, by the quantum computer, the purified quantum state to determine properties of the target system.

16. The quantum data processing system of claim 15 , wherein the quantum sensor is configured to maintain quantum coherence.

17. The quantum data processing system of claim 15 , wherein the evolved quantum state of the quantum sensor encodes properties of the target system at the time of the probing.

18. The quantum data processing system of claim 15 , wherein the evolved quantum state of the quantum sensor comprises a state of multiple qubits or a state of bosonic or photonic modes.

19. The quantum data processing system of claim 15 , wherein the quantum sensor is configured to probe the target system to evolve the quantum state of the quantum sensor with finite signal to noise ratio.

20. The quantum data processing system of claim 15 , wherein the quantum sensor is configured to implement full or partial quantum error correction on the evolved quantum state of the quantum sensor.

21. The quantum data processing system of claim 15 , wherein the quantum sensor comprises a first computational medium and the quantum buffer comprises a second computational medium, wherein the second computational medium is different to the first computational medium.

22. The quantum data processing system of claim 15 , wherein the quantum data processing system is configured to logically encode the quantum state of the quantum buffer into a quantum error correcting code through application of a unitary encoding quantum circuit to the quantum state of the quantum buffer or through performance of a state injection technique.

23. The quantum data processing system of claim 15 , wherein the quantum error correcting code comprises a code distance that is dependent on at least one of: operations performed by the quantum computer to obtain the purified quantum state or an expected duration required to store the multiple copies of the quantum state.

24. The quantum data processing system of claim 15 , wherein the quantum error correcting code is the quantum buffer.

25. The quantum data processing system of claim 15 , wherein the quantum computing device is configured to process the multiple copies of the quantum state to obtain a purified quantum state by performing a linear distillation technique to purify the multiple copies of the quantum state.

26. The quantum data processing system of claim 25 , wherein the linear distillation technique comprises quantum state distillation, virtual state distillation or a quantum principle component analysis algorithm.

27. The quantum data processing system of claim 15 , wherein the quantum computing device is configured to provide measurement results obtained by measuring the purified quantum state to a quantum machine learning system to learn the properties of the target system.

28. The quantum data processing system of claim 15 , wherein the target system comprises a transient target system.