74 research outputs found
Erasure-cooling, control, and hyper-entanglement of motion in optical tweezers
We demonstrate how motional degrees of freedom in optical tweezers can be
used as quantum information carriers. To this end, we first implement a
species-agnostic cooling mechanism via conversion of motional excitations into
erasures - errors with a known location - reminiscent of Maxwell's demon
thought experiment. We find that this cooling mechanism fundamentally
outperforms idealized traditional sideband cooling, which we experimentally
demonstrate in specific scenarios. By coherently manipulating the motional
state, we perform mid-circuit readout and mid-circuit erasure detection of an
optical qubit via local shelving into motional superposition states. We finally
entangle the motion of two atoms in separate tweezers, and utilize this to
generate hyper-entanglement by preparing a simultaneous Bell state of motional
and optical qubits. This work shows how controlling motion enriches the toolbox
of quantum information processing with neutral atoms, and opens unique
prospects for metrology enhanced by mid-circuit readout and a large class of
quantum operations enabled via hyper-entanglement.Comment: PS, ALS and RF contributed equally to this wor
Erasure conversion in a high-fidelity Rydberg quantum simulator
Minimizing and understanding errors is critical for quantum science, both in
noisy intermediate scale quantum (NISQ) devices and for the quest towards
fault-tolerant quantum computation. Rydberg arrays have emerged as a prominent
platform in this context with impressive system sizes and proposals suggesting
how error-correction thresholds could be significantly improved by detecting
leakage errors with single-atom resolution, a form of erasure error conversion.
However, two-qubit entanglement fidelities in Rydberg atom arrays have lagged
behind competitors and this type of erasure conversion is yet to be realized
for matter-based qubits in general. Here we demonstrate both erasure conversion
and high-fidelity Bell state generation using a Rydberg quantum simulator. We
implement erasure conversion via fast imaging of alkaline-earth atoms, which
leaves atoms in a metastable state unperturbed and yields additional
information independent of the final qubit readout. When excising data with
observed erasure errors, we achieve a lower-bound for the Bell state generation
fidelity of , which improves to
when correcting for remaining state preparation
errors. We further demonstrate erasure conversion in a quantum simulation
experiment for quasi-adiabatic preparation of long-range order across a quantum
phase transition, where we explicitly differentiate erasure conversion of
preparation and Rydberg decay errors. We unveil the otherwise hidden impact of
these errors on the simulation outcome by evaluating correlations between
erasures and the final readout as well as between erasures themselves. Our work
demonstrates the capability for Rydberg-based entanglement to reach fidelities
in the regime, with higher fidelities a question of technical
improvements, and shows how erasure conversion can be utilized in NISQ devices.Comment: PS and ALS contributed equally to this wor
Multi-ensemble metrology by programming local rotations with atom movements
Current optical atomic clocks do not utilize their resources optimally. In
particular, an exponential gain could be achieved if multiple atomic ensembles
were to be controlled or read-out individually, even without entanglement.
However, controlling optical transitions locally remains an outstanding
challenge for neutral atom based clocks and quantum computing platforms. Here
we show arbitrary, single-site addressing for an optical transition via
sub-wavelength controlled moves of tweezer-trapped atoms, which we perform with
fidelity and with crosstalk to non-addressed atoms. The
scheme is highly robust as it relies only on relative position changes of
tweezers and requires no additional addressing beams. Using this technique, we
implement single-shot, dual-quadrature readout of Ramsey interferometry using
two atomic ensembles simultaneously, and show an enhancement of the usable
interrogation time at a given phase-slip error probability, yielding a 2.55(9)
dB gain over standard, single-ensemble methods. Finally, we program a sequence
which performs local dynamical decoupling during Ramsey evolution to evolve
three ensembles with variable phase sensitivities, a key ingredient of optimal
clock interrogation. Our results demonstrate the potential of fully
programmable quantum optical clocks even without entanglement and could be
combined with metrologically useful entangled states in the future
Benchmarking highly entangled states on a 60-atom analog quantum simulator
Quantum systems have entered a competitive regime where classical computers
must make approximations to represent highly entangled quantum states. However,
in this beyond-classically-exact regime, fidelity comparisons between quantum
and classical systems have so far been limited to digital quantum devices, and
it remains unsolved how to estimate the actual entanglement content of
experiments. Here we perform fidelity benchmarking and mixed-state entanglement
estimation with a 60-atom analog Rydberg quantum simulator, reaching a high
entanglement entropy regime where exact classical simulation becomes
impractical. Our benchmarking protocol involves extrapolation from comparisons
against many approximate classical algorithms with varying entanglement limits.
We then develop and demonstrate an estimator of the experimental mixed-state
entanglement, finding our experiment is competitive with state-of-the-art
digital quantum devices performing random circuit evolution. Finally, we
compare the experimental fidelity against that achieved by various approximate
classical algorithms, and find that only one, which we introduce here, is able
to keep pace with the experiment on the classical hardware we employ. Our
results enable a new paradigm for evaluating the performance of both analog and
digital quantum devices in the beyond-classically-exact regime, and highlight
the evolving divide between quantum and classical systems.Comment: ALS, ZC, and JC contributed equall
HRS1 Acts as a Negative Regulator of Abscisic Acid Signaling to Promote Timely Germination of Arabidopsis Seeds
In this work, we conducted functional analysis of Arabidopsis HRS1 gene in order to provide new insights into the mechanisms governing seed germination. Compared with wild type (WT) control, HRS1 knockout mutant (hrs1-1) exhibited significant germination delays on either normal medium or those supplemented with abscisic acid (ABA) or sodium chloride (NaCl), with the magnitude of the delay being substantially larger on the latter media. The hypersensitivity of hrs1-1 germination to ABA and NaCl required ABI3, ABI4 and ABI5, and was aggravated in the double mutant hrs1-1abi1-2 and triple mutant hrs1-1hab1-1abi1-2, indicating that HRS1 acts as a negative regulator of ABA signaling during seed germination. Consistent with this notion, HRS1 expression was found in the embryo axis, and was regulated both temporally and spatially, during seed germination. Further analysis showed that the delay of hrs1-1 germination under normal conditions was associated with reduction in the elongation of the cells located in the lower hypocotyl (LH) and transition zone (TZ) of embryo axis. Interestingly, the germination rate of hrs1-1 was more severely reduced by the inhibitor of cell elongation, and more significantly decreased by the suppressors of plasmalemma H+-ATPase activity, than that of WT control. The plasmalemma H+-ATPase activity in the germinating seeds of hrs1-1 was substantially lower than that exhibited by WT control, and fusicoccin, an activator of this pump, corrected the transient germination delay of hrs1-1. Together, our data suggest that HRS1 may be needed for suppressing ABA signaling in germinating embryo axis, which promotes the timely germination of Arabidopsis seeds probably by facilitating the proper function of plasmalemma H+-ATPase and the efficient elongation of LH and TZ cells
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