Quantum technologies need a Quantum Energy Initiative

Abstract

Quantum technologies are currently the object of high expectations from governments and private companies, as they hold the promise to shape safer and faster ways to exchange and treat information. However, despite its major potential impact for industry and society, the question of their energetic footprint has remained in a blind spot of current deployment strategies. In this Perspective, I argue that quantum technologies must urgently plan for the creation and structuration of a transverse quantum energy initiative, connecting quantum thermodynamicists, computer scientists, experimenters and engineers. Such initiative is the only path towards sustainable quantum technologies, help reducing the cost of classical information processing, and possibly bring out an energetic quantum advantage.

Quantum thermodynamic devices: from theoretical proposals to experimental reality

“…The internal energy of the system can be found from, E = H = tr {ρ eq H} . (11) For the Gibbs state, the thermodynamic entropy is given by the Gibbs entropy, S = −tr {ρ eq ln ρ eq }. For an isothermal, quasistatic process the change in entropy is then 12 , dS = β tr {dρ eq H} .…”

“…Using Eq. (11) we can separate the change in internal energy, dE into two contributions, one associated with a change in entropy and the other from a change in the Hamiltonian 12 , dE = tr {dρ eq H} + tr {ρ eq dH} ≡ dQ + dW. (13) In complete analogy to classical thermodynamics we can define the first as heat and the second as work.…”

“…However, very similar to the situation the public faced at the invention of steam engines, new quantum technologies are complex 9 and markedly different from what societies are used to 10 . While many fundamental as well as quite practical questions remain to be addressed 11 , it does appear obvious that a thermodynamic approach to quantum technologies may provide an effective and pedagogical entry point for a large audience.…”

Periodically refreshed quantum thermal machines

“…Moreover, our proposal for physically realizing the PReB process requires a finite number of control parameters, making the experimental implementation of the unique thermodynamic cycle plausible. This will, in turn, open different pathways for efficient management of energy at microscopic levels, which is crucial for development of quantum technology [33].…”

From quantum speed limits to energy-efficient quantum gates

“…While the asymptotic scaling of resource usage with problem size on quantum computers is increasingly well understood [15], there has been less emphasis placed on calculating the coefficients which determine this dependence exactly; that is, it may be known that an algorithm can be executed in an amount of time which is proportional to a particular function of the input size, but the constant of proportionality is seldom known precisely. This is partly because the coefficients differ from one machine to another, and are therefore not fundamentally properties of the algorithm [16].…”