5 research outputs found
Scalable photonic integrated circuits for programmable control of atomic systems
Advances in laser technology have driven discoveries in atomic, molecular,
and optical (AMO) physics and emerging applications, from quantum computers
with cold atoms or ions, to quantum networks with solid-state color centers.
This progress is motivating the development of a new generation of
"programmable optical control" systems, characterized by criteria (C1) visible
(VIS) and near-infrared (IR) wavelength operation, (C2) large channel counts
extensible beyond 1000s of individually addressable atoms, (C3) high intensity
modulation extinction and (C4) repeatability compatible with low gate errors,
and (C5) fast switching times. Here, we address these challenges by introducing
an atom control architecture based on VIS-IR photonic integrated circuit (PIC)
technology. Based on a complementary metal-oxide-semiconductor (CMOS)
fabrication process, this Atom-control PIC (APIC) technology meets the system
requirements (C1)-(C5). As a proof of concept, we demonstrate a 16-channel
silicon nitride based APIC with (5.80.4) ns response times and -30 dB
extinction ratio at a wavelength of 780 nm. This work demonstrates the
suitability of PIC technology for quantum control, opening a path towards
scalable quantum information processing based on optically-programmable atomic
systems
Partial Compilation of Variational Algorithms for Noisy Intermediate-Scale Quantum Machines
Quantum computing is on the cusp of reality with Noisy Intermediate-Scale
Quantum (NISQ) machines currently under development and testing. Some of the
most promising algorithms for these machines are variational algorithms that
employ classical optimization coupled with quantum hardware to evaluate the
quality of each candidate solution. Recent work used GRadient Descent Pulse
Engineering (GRAPE) to translate quantum programs into highly optimized machine
control pulses, resulting in a significant reduction in the execution time of
programs. This is critical, as quantum machines can barely support the
execution of short programs before failing.
However, GRAPE suffers from high compilation latency, which is untenable in
variational algorithms since compilation is interleaved with computation. We
propose two strategies for partial compilation, exploiting the structure of
variational circuits to pre-compile optimal pulses for specific blocks of
gates. Our results indicate significant pulse speedups ranging from 1.5x-3x in
typical benchmarks, with only a small fraction of the compilation latency of
GRAPE.Comment: Appearing in the 52nd Annual IEEE/ACM International Symposium on
Microarchitecture (MICRO-52), October 12-16, 2019, Columbus, OH, US
Valve stroking to control transient flows in liquid piping systems
http://deepblue.lib.umich.edu/bitstream/2027.42/7180/5/bad1185.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/7180/4/bad1185.0001.001.tx