Bridging quantum mechanics and thermodynamics
Why does the world rarely manifest its quantum nature (“quantumness”) on macroscales?
The standard answer is that macrosystems are so complex that they can be treated as “reservoirs” characterized by temperature (thermal “baths”) as opposed to simple, typically nanoscale, systems totally isolated from their environment that can reveal quantumness. However, environments describable as thermal baths are ubiquitously in contact with quantum systems. As a result, all quantum systems are “open” – subject to coherence loss or decoherence by their environment/bath. This fact hinders the development of quantum technologies that rely on quantum coherence, particularly quantum computers.
The fundamental challenge is greater: how to bridge quantum mechanics, whereby systems evolve coherently and reversibly in time, with thermodynamics whereby systems in contact with a thermal bath/environment irreversibly evolve towards thermal equilibrium with the bath and lose their coherence? This foundational issue underlies the concept of Time Arrow Reversibility, on which we have obtained spectacular theoretical and experimental results. To mitigate the unwarranted environment effects, we have introduced a universal Dynamical Decoherence Control, aimed at suppressing bath-induced decoherence or dissipation in quantum systems. Yet often such control does not yield the desired results, hence we advocate a different strategy that may be colloquially summarized as follows: 'if you can't fight the bath–join it', namely, take advantage of bath effects as quantum resources. To this end, we study:
Thermodynamic Control of Quantum Systems, aimed at building heat machines (heat engines, refrigerators, heat transistors) for the quantum domain, the issue being: Are there quantum advantages to heat machines based on quantum systems? Thermal bath effects, resulting in noise in quantum systems that is commonly viewed as a nuisance to be suppressed, but we show that we can employ Noise as a Source of Sensing Information.
Bath-induced quantum entanglement and dispersive forces: We show that, surprisingly, thermal baths not only hamper quantum coherence and entanglement but, on the contrary, can be a source of quantum entanglement. A bath can also promote quantum information processing and transfer in Quantum Hybrid Systems, a key concept in quantum technologies pioneered by us.
Our selected publications on these issues:
G. Kurizki and A.G. Kofman, Thermodynamics and Control of Open Quantum Systems (Cambridge University Press, 2022)
Kurizki and G. Gordon, The Quantum Matrix: Henry Bar’s Perilous Struggle for Quantum Coherence (Oxford University Press, 2020)
Kurizki, G.; Shahmoon, E.; Zwick, A. (2015). Thermal Baths as Quantum Resources: More Friends Than Foes?. Physica Scripta. 90:128002 (15 pp.)