Seminars Archive

Ultrafast Switching to a Stable Hidden Quantum State in an Electronic Crystal

Abstract
Hidden states are distinct from thermodynamic phases of matter, and cannot be reached under ergodic conditions. We present an example where a hidden many body quantum state is reached under non-equilibrium conditions by laser excitation of an electronic crystal (TaS2) (1). The mechanism relies on the separation of the fundamental degrees of freedom under nonequilibrium conditions: a transient particle-hole asymmetry creates conditions under which a long-range ordered state is formed, which is topologically distinct from the ground state. The long range order and topology ensures long-term stability of the quantum state (2,3). I will show different ways to manipulate the hidden state transition experimentally discuss the conditions for treating the transition to the hidden state in terms of macroscopic quantum tunneling between many-body states. The discovery of electrical switching (4) leads to new concepts in data storage with record speeds and ultralow energy per bit, on par with magnetic memories. 1. Stojchevska, L. et al. Ultrafast switching to a stable hidden quantum state in an electronic crystal. Science 344, 177–180 (2014). 2. Svetin, D. et al. Transitions between photoinduced macroscopic quantum states in 1T-TaS 2controlled by substrate strain. Appl. Phys. Express 7, 103201 (2014). 3. Vaskivskyi, I. et al. Controlling the metal-to-insulator relaxation of the metastable hidden quantum state in 1T-TaS2. Science Advances 1, e1500168–e1500168 (2015). 4. Vaskivskyi, I. et al. Fast non-thermal switching between macroscopic charge-ordered quantum states induced by charge injection., arXiv:1409.3794 (2014).