A scalable hardware and software control apparatus for experiments with hybrid quantum systems

Abstract

Modern experiments with fundamental quantum systems -like ultracold atoms, trapped ions, single photons -are managed by a control system formed by a number of input/output electronic channels governed by a computer. In hybrid quantum systems, where two or more quantum systems are combined and made to interact, establishing an efficient control system is particularly challenging due to the higher complexity, especially when each single quantum system is characterized by a different timescale. Here we present a new control apparatus specifically designed to efficiently manage hybrid quantum systems. The apparatus is formed by a network of fast communicating Field Programmable Gate Arrays (FPGAs), the action of which is administrated by a software. Both hardware and software share the same tree-like structure, which ensures a full scalability of the control apparatus. In the hardware, a master board acts on a number of slave boards, each of which is equipped with an FPGA that locally drives analog and digital input/output channels and radiofrequency (RF) outputs up to 400 MHz. The software is designed to be a general platform for managing both commercial and home-made instruments in a user-friendly and intuitive Graphical User Interface (GUI). The architecture ensures that complex control protocols can be carried out, such as performing of concurrent commands loops by acting on different channels, the generation of multi-variable error functions and the implementation of self-optimization procedures. Although designed for managing experiments with hybrid quantum systems, in particular with atom-ion mixtures, this control apparatus can in principle be used in any experiment in atomic, molecular, and optical physics.

Phase-Noise and Amplitude-Noise Measurement of DACs and DDSs

“…We introduce the approximation that S α1 S α2 and S ϕ1 S ϕ2 , based on the fact that the two DACs are nominally equal. Thus, it makes sense to approximate (15) as…”

“…Putting ( 20)-( 23) into (15) and expanding (18), we get a general expression for A . The derivation of A and the subsequent manipulations are done with a symbolic math app (Wolfram Mathematica).…”

“…The second case is the accuracy of (18) for θ = 0, still under the assumption that the noise of the two DACs is equal. For this purpose, we allow a small angle error ζ, and we expand (15) in series truncated to the second order of η and ζ. For θ = 0, replacing θ → ζ gives…”

“…For example, 1/η 2 = 100 (20 dB) results in 1.1×10 −2 dB error in (25), and in −26 dB coupling between AM and PM in (26). Of course, the gain must be well calibrated because of the 1/η 2 factor in (15). The angle error deserves more attention.…”

“…The relevant parameters are low PM and AM noise, high stability, frequency agility, and programmable amplitude and phase. We have in mind general purpose instruments, Atomic-Molecular-Optics physics and atomic clocks [14], [15], [16], longdistance synchronization via fiber links [17], [18], [19], realtime phase measurements [20], particle accelerators [21], etc.…”