It is known that entanglement can be converted to work in quantum composite systems. In this paper we consider a quench protocol for two initially independent reservoirs $A$ and $B$ described by the quantum thermal states. For a free fermion model at
low temperatures, the von Neumann entropy of each reservoir increases once the reservoirs are coupled. At the moment of decoupling there is an energy transfer to the system in the amount set by the von Neumann entropy accumulated during joint evolution of $A$ and $B$. This energy transfer appears as work produced by the quench to decouple the reservoirs. Once the reservoirs are disconnected, the information about their mutual correlations $-$ von Neumann entropy $-$ is stored in the energy increment of each reservoir. This result provides a possibility of a direct readout of quantum correlations at low temperature.
The Sachdev-Ye-Kitaev (SYK) model describes interacting fermionic zero modes in zero spatial dimensions, e.g. quantum dot, with interactions strong enough to completely washout quasiparticle excitations in the infrared. In this note, we consider the
complex-valued SYK model at temperature $T$ coupled to a zero temperature reservoir by a quench. We find out that the tunneling current dynamics reveals a way to distinguish the SYK non-Fermi liquid (nFL) initial state of the subsystem from the disordered Fermi liquid. Temperature dependent contribution to the currents half-life scales linearly in $T$ at low temperatures for the SYK nFl state, while for the Fermi liquid it scales as $T^2$. This provides a characteristic signature of the SYK non-Fermi liquid in a non-equilibrium measurement.
The Planckian relaxation rate $hbar/t_mathrm{P} = 2pi k_mathrm{B} T$ sets a characteristic time scale for both equilibration of quantum critical systems and maximal quantum chaos. In this note, we show that at the critical coupling between a supercon
ducting dot and the complex Sachdev-Ye-Kitaev model, known to be maximally chaotic, the pairing gap $Delta$ behaves as $eta ,, hbar/t_mathrm{P}$ at low temperatures, where $eta$ is an order one constant. The lower critical temperature emerges with a further increase of the coupling strength so that the finite $Delta$ domain is settled between the two critical temperatures.
