DOI: 10.5061/dryad.9p8cz8wqn
title: High-rate generation and state tomography of non-gaussian quantum states for ultra-fast clock frequency quantum processors

description: Quantum information processors greatly benefit from high clock frequency.
 All-optical systems offer unique advantages due to their inherent 100 THz
 carrier frequency, permitting one to develop THz clock frequency
 processors. In practice, the bandwidth of the quantum light sources and
 the measurement devices has been limited to the MHz range and the
 generation rate of nonclassical states to kHz order In this work, we go
 beyond this limitation by utilizing optical parametric amplifier (OPA) as
 a squeezed-light source and optical phase-sensitive amplifiers (PSA) to
 realize high-rate generation of broadband non-Gaussian states and their
 quantum tomography. Our system consists of a 6-THz squeezed-light source,
 a 6-THz PSA, and a 66-GHz homodyne detector. We have successfully
 demonstrated non-Gaussian state generation at a 0.9 MHz rate---almost
 three orders of magnitude higher than the current state-of-the-art
 experiments---with a sub-nanosecond wave packet using continuous-wave
 laser. The performance is constrained only by the superconducting
 detector's jitter which currently limits the usable bandwidth of the
 squeezed light to 1 GHz.
description: This data was collected by homodyne measurement on
 photon-subtracted state generated. The photon-subtracted state is
 generated by tapping a small portion of squeezed light generated from an
 optical parametric amplifier, and then send the tapped light to a photon
 counter. The data processed by integration of the real-time data collected
 from the oscilloscope into the quadrature of each wave packet.
description: # High-rate Generation and State Tomography of Non-Gaussian Quantum States
 for Ultra-fast Clock Frequency Quantum Processors
 [https://doi.org/10.5061/dryad.9p8cz8wqn](https://doi.org/10.5061/dryad.9p8cz8wqn) This data is the quadrature data measured at the various phase of the quantum state. The experiment where this data was taken from is a quantum optics experiment using continuous-wave laser of wavelength 1545.32 nm. The quantum state generated here is a quantum state called photon-subtracted state (PSS) which is known to be a good approximation to Schrodigner's cat states. In the generation of PSS, there are two related parameters we used in the experiment. The first paramter is the squeezing level of the initial squeezed states determined by the pump power of the optical parametric amplifier. The second parameter is an excess loss we added in the experiment. Regarding the second parameter, to perform a quantum tomography we have a phase sensitive amplifier which amplifies the quantum signal to classical signal. To show that the signals indeed became classical signal, we add additional optical losses and see how they affect the quantum tomography results. ## Description of the data and file structure The data is of the type .mat which is a MATLAB file. Each file is has the name of the structure "quad_01GHZ_xxmW_yydB.mat", where the "xx" is the pump power of the optical parametric amplifier and yy is the amount of excess loss that was added in the experiment. See the related paper for more description of the experimental setup. The .mat file contains various array type variable of size 1x5000. The variable name is of the form "pzzdeg" where "zz" is the number showing the measurement phase in degree. Each point is a quadrature value of each event and the quadrature values are calculated in a dimensionless unit with hbar = 1/2.