Compressed sensing is a processing method that significantly reduces the number of measurements needed to accurately resolve signals in many fields of science and engineering. We develop a two-dimensional (2D) variant of compressed sensing for multid
imensional electronic spectroscopy and apply it to experimental data. For the model system of atomic rubidium vapor, we find that compressed sensing provides significantly better resolution of 2D spectra than a conventional discrete Fourier transform from the same experimental data. We believe that by combining powerful resolution with ease of use, compressed sensing can be a powerful tool for the analysis and interpretation of ultrafast spectroscopy data.
We present an adiabatic approach to the design of entangling quantum operations with two electron spins localized in separate InAs/GaAs quantum dots via the Coulomb interaction between optically-excited localized states. Slowly-varying optical pulses
minimize the pulse noise and the relaxation of the excited states. An analytic dressed state solution gives a clear physical picture of the entangling process, and a numerical solution is used to investigate the error dynamics. For two vertically-stacked quantum dots we show that, for a broad range of dot parameters, a two-spin state with concurrence $C>0.85$ can be obtained by four optical pulses with durations $sim 0.1 - 1$ ns.
