Nonlinear interactions in quantum systems

Marek Czachor

Qi Geng, Ka‐Di Zhu

We have theoretically investigated a hybrid system that is composed of a traditional optomechanical component and an additional charge qubit (Cooper pair box) that induces a new nonlinear interaction. It is shown that the peak in optomechanically induced transparency has been split by the new nonlinear interaction, and the width of the splitting is proportional to the coupling coefficient of this nonlinear interaction. This may give a way to measure the nanomechanical oscillator-qubit coupling coefficient in hybrid quantum systems.

Salman Habib

Petr Marek, Radim Filip, Hisashi Ogawa +4 more

We propose general methodology of deterministic single-mode quantum interaction nonlinearly modifying single quadrature variable of a continuous-variable system. The methodology is based on linear coupling of the system to ancillary systems subsequently measured by quadrature detectors. The nonlinear interaction is obtained by using the data from the quadrature detection for dynamical manipulation of the coupling parameters. This measurement-induced methodology enables direct realization of arbitrary nonlinear quadrature interactions without the need to construct them from the lowest-order gates. Such nonlinear interactions are crucial for more practical and efficient manipulation of continuous quadrature variables as well as qubits encoded in continuous-variable systems.

J. R. Croca, João L. Cordovil

Salvatore Savasta, R. Girlanda

We present a theory of the nonlinear optical response of cavity embedded interacting electron systems which does not rely on semiclassical factorization. The theory provides a unified basis for understanding nonlinear quantum dynamics in cavity embedded quantum wells. Nonclassical behavior of transmitted light is found.