Quantum state tomography of 1D resonance fluorescence
Ingrid Strandberg
Abstract
Tomography is the name under which all state reconstruction techniques are denoted,\none of the most recognized examples being medical tomography. Quantum\nstate tomography is a procedure to determine the quantum state of a physical system.\nBy performing homodyne measurements on resonance fluorescence from an\nartificial atom coupled to a one-dimensional transmission line, its quantum state\ncan be reconstructed. Resonance fluorescence is one of the simplest setups that\nresults in non-classical states of light. If these states are non-classical in the sense\nthat they have a negative Wigner function, they can be used as a computational\nresource for quantum computing.\nThere are many different approaches to quantum computing. Some, like gate\nbased quantum computing using discrete variables like qubits, have been extensively\nresearched, both theoretically and experimentally. There exists and alternative\napproach: continuous variable quantum computing. The continuous variables\nwe will be concerned with are the components of the electromagnetic field that\nconstitute the resonance fluorescence.\nThere are different parameters that affect the nature of the resonance fluorescence,\nfor example, the number of transmission lines the atom is coupled to, or\nthe strength of the driving field. In this work, we develop the tools necessary to\nnumerically simulate homodyne detection of resonance fluorescence for different\nsets of parameters, and reconstruct the quantum state as well as calculating the\nWigner negativity.