Time Reversal and Charge Conjugation in an Embedding Quantum Simulator
  The understanding of symmetry operations has brought enormous advancements in physics, ranging from elementary particle to condensed matter systems. In quantum mechanics, symmetry operations are described by either unitary or antiunitary operators, where the latter are unphysical transformations that cannot be realized in physical systems. So far, quantum simulators of unitary and dissipative processes, the only allowed physical dynamics, have been realized in key experiments. Here, we present an embedding quantum simulator able to encode unphysical operations in a multilevel single trapped ion. In this sense, we experimentally observe phenomena associated with the nonunitary Majorana dynamics and implement antiunitary symmetry operations, i.e., time reversal and charge conjugation, at arbitrary evolution times. These experiments enhance the toolbox of quantum simulations towards applications involving unphysical operations. 
Xiang Zhang, Yangchao Shen, Junhua Zhang, Jorge Casanova, Lucas   Lamata, Enrique Solano, Man-Hong Yung, Jing-Ning Zhang, Ki...
quant-ph cond-mat.mes-hall gr-qc hep-th