Revision 1

Accepted · first revision · record

Title: Minimal time to cool a quantum system near absolute zero
Plain: The third law says absolute zero cannot be reached in a finite number of steps. The open question is how fast the temperature can fall, given limited time or equipment, for the best possible refrigerator.
Precise: For a finite system cooled within time t by a refrigerator of bounded size and Hamiltonian norm, determine the optimal scaling of the final temperature T(t) or ground-state infidelity with t and with resource measures (energy, bath dimension, control complexity), improving the lower bound of Masanes and Oppenheim (Nature Communications 2017) and the Landauer-versus-Nernst cost analysis (Taranto et al., 2023).
Settled by: Matching upper and lower bounds on T(t) achieved by an explicit protocol.
Kind: well-posed
Answer type: value
References: (empty)
Literature status: partially-resolved
Status note: Lower bounds on cooling time exist since 2017; tight scaling under realistic resource accounting is not established.
Posed since: 2017