Method for decreasing entropy in a quantum system

1. A method for decreasing entropy in a system comprising a target system having one or more target elements each having a first relaxation time, the target system having a set of target system energy levels, and a reset system having one or more reset elements each having a second relaxation time that is shorter than the first relaxation time, the reset system having a set of reset system energy levels, the system having a set of system energy levels that includes the possible combinations of target system energy levels and the reset system energy levels, the method comprising:

iteratively, for a plurality of iterations:

applying a set of electromagnetic (EM) pulses to the system, the set of EM pulses effect swaps between the following pairs of system energy levels:

a first system energy level in which the reset system is in a lowest energy level of the set of reset system energy levels and the target system is in a first target system energy level that is not a lowest energy level of the set of target system energy levels, and

a corresponding second system energy level in which the reset system is in a highest energy level of the set of reset system energy levels and the target system is in a second target system energy level that is next lowest in energy after the first target system energy level; and

waiting a time period that is on the order of the second relaxation time and shorter than the first relaxation time to facilitate at least some of the reset elements of the reset system resetting from the highest energy state.

2. The method of claim 1 , wherein the target elements are spins.

3. The method of claim 2 , wherein each target element is a multilevel quantum system.

4. The method of claim 3 , wherein the multilevel quantum system is one of spin 1 particles and nitrogen vacancy (nv) centers.

5. The method of claim 1 , wherein the reset elements are spins.

6. The method of claim 5 , wherein each reset element is a multilevel quantum system.

7. The method of claim 6 , wherein the multilevel quantum system is one of spin 1 particles and nitrogen vacancy (nv) centers.

8. The method of claim 1 , wherein the target elements and the reset elements are spins.

9. The method of claim 8 , wherein the target elements are comprised of a spin species different than the reset elements.

10. The method of claim 1 , wherein one or both of the target elements and the reset elements are qubits.

11. The method of claim 1 , wherein the set of EM pulses are applied to implement a sequence of quantum logic gates in order to effect swaps between the pairs of first quantum system energy levels and corresponding second quantum system energy levels.

12. The method of claim 11 , wherein the quantum logic gates include a shift forward gate, a Toffoli gate, an X gate, and a shift back gate.

13. The method of claim 1 , wherein the second relaxation time is an effective relaxation time that is shorter than an intrinsic relaxation time of the reset elements.

14. The method of claim 1 , wherein each iteration further comprises, during the waiting, manipulating the reset system to reduce the second relaxation time from the intrinsic relaxation time to the effective relaxation time.

15. The method of claim 14 , wherein manipulating the reset system comprises performing one of optical polarization, optical pumping, and dynamic nuclear polarization.

16. The method of claim 1 , wherein at least some of the pairs of first system energy levels and the corresponding second system energy levels correspond to one of entangled system states or non-diagonal system states.