Quantum Simulation of the Majorana Equation and Unphysical Operations
  A quantum simulator is a device engineered to reproduce the properties of an ideal quantum model. It allows the study of quantum systems that cannot be efficiently simulated on classical computers. While a universal quantum computer is also a quantum simulator, only particular systems have been simulated up to now. Still, there is a wealth of successful cases, such as spin models, quantum chemistry, relativistic quantum physics and quantum phase transitions. Here, we show how to design a quantum simulator for the Majorana equation, a non-Hamiltonian relativistic wave equation that might describe neutrinos and other exotic particles beyond the standard model. The simulation demands the implementation of charge conjugation, an unphysical operation that opens a new front in quantum simulations, including the discrete symmetries associated with complex conjugation and time reversal. Finally, we show how to implement this general method in trapped ions. 
J. Casanova, C. Sabin, J. Leon, I. L. Egusquiza, R. Gerritsma, C. F.   Roos, J. J. Garcia-Ripoll, E. Solano
quant-ph cond-mat.mes-hall cond-mat.quant-gas hep-th