Various quantum applications can be reduced to estimating expectation values, which are inevitably deviated by operational and environmental errors. Although errors can be tackled by quantum error ...correction, the overheads are far from being affordable for near-term technologies. To alleviate the detrimental effects of errors on the estimation of expectation values, quantum error mitigation techniques have been proposed, which require no additional qubit resources. Here we benchmark the performance of a quantum error mitigation technique based on probabilistic error cancellation in a trapped-ion system. Our results clearly show that effective gate fidelities exceed physical fidelities, i.e., we surpass the break-even point of eliminating gate errors, by programming quantum circuits. The error rates are effectively reduced from (1.10 ± 0.12) × 10
to (1.44 ± 5.28) × 10
and from (0.99 ± 0.06) × 10
to (0.96 ± 0.10) × 10
for single- and two-qubit gates, respectively. Our demonstration opens up the possibility of implementing high-fidelity computations on a near-term noisy quantum device.
Fluorescent probes along with fluorescence microscopy are essential tools for biomedical research. Various cellular ubiquitous chemical factors such as pH, H
O
, and Ca
are labeled and traced using ...specific fluorescent probes, therefore helping us to explore their physiological function and pathological change. Among them, intracellular pH value is an important factor that governs biological processes, generally ∼7.2. Furthermore, specific organelles within cells possess unique acid-base homeostasis, involving the acidic lysosomes, alkalescent mitochondria, and neutral endoplasmic reticulum and Golgi apparatus, which undergo various physiological processes such as intracellular digestion, ATP production, and protein folding and processing. In this review, recently reported fluorescent probes targeted toward the lysosomes, mitochondria, endoplasmic reticulum, Golgi apparatus, and cytoplasm for sensing pH change are discussed, which involves molecular structures, fluorescence behavior, and biological applications.
A long-time quantum memory capable of storing and measuring quantum information at the single-qubit level is an essential ingredient for practical quantum computation and communication1,2. Currently, ...the coherence time of a single qubit is limited to less than 1 min, as demonstrated in trapped ion systems3–5, although much longer coherence times have been reported in ensembles of trapped ions6,7 and nuclear spins of ionized donors8,9. Here, we report the observation of a coherence time of over 10 min for a single qubit in a 171Yb+ ion sympathetically cooled by a 138Ba+ ion in the same Paul trap, which eliminates the problem of qubit-detection inefficiency from heating of the qubit ion10,11. We also apply a few thousand dynamical decoupling pulses to suppress ambient noise from magnetic-field fluctuations and phase noise from the local oscillator8,9,12–16. The long-time quantum memory of the single trapped ion qubit would be the essential component of scalable quantum computers1,17,18, quantum networks2,19,20 and quantum money21,22.
The quantum Rabi model, involving a two-level system and a bosonic field mode, is arguably the simplest and most fundamental model describing quantum light-matter interactions. Historically, due to ...the restricted parameter regimes of natural light-matter processes, the richness of this model has been elusive in the lab. Here, we experimentally realize a quantum simulation of the quantum Rabi model in a single trapped ion, where the coupling strength between the simulated light mode and atom can be tuned at will. The versatility of the demonstrated quantum simulator enables us to experimentally explore the quantum Rabi model in detail, including a wide range of otherwise unaccessible phenomena, as those happening in the ultrastrong and deep strong-coupling regimes. In this sense, we are able to adiabatically generate the ground state of the quantum Rabi model in the deep strong-coupling regime, where we are able to detect the nontrivial entanglement between the bosonic field mode and the two-level system. Moreover, we observe the breakdown of the rotating-wave approximation when the coupling strength is increased, and the generation of phonon wave packets that bounce back and forth when the coupling reaches the deep strong-coupling regime. Finally, we also measure the energy spectrum of the quantum Rabi model in the ultrastrong-coupling regime.
Counterdiabatic driving (CD) exploits auxiliary control fields to tailor the nonequilibrium dynamics of a quantum system, making possible the suppression of dissipated work in finite-time ...thermodynamics and the engineering of optimal thermal machines with no friction. We show that while the mean work done by the auxiliary controls vanishes, CD leads to a broadening of the work distribution. We derive a fundamental inequality that relates nonequilibrium work fluctuations to the operation time and quantifies the thermodynamic cost of CD in both critical and noncritical systems.
Plant extracellular vesicles (EVs) are membrane-enclosed nanoparticles that play diverse roles in plant development and response. Recently, impressive progress has been made in the isolation and ...identification of the proteins and RNAs carried in plant EVs; however, the analysis of EV lipid compositions remains rudimentary. Here, we performed lipidomic analysis of Arabidopsis rosette leaf EVs, revealing a high abundance of certain groups of lipids, in particular sphingolipids, in the EVs. Remarkably, the EV sphingolipids are composed of nearly pure glycosylinositolphosphoceramides (GIPCs), which are green lineage abundant and negatively charged. We further showed that the Arabidopsis TETRASPANIN 8 (TET8) knockout mutant has a lower amount of cellular GIPCs and secrets fewer EVs, companied with impaired reactive oxygen species (ROS) burst toward stresses. Exogenous application of GIPCs promoted the secretion of EVs and ROS burst in both the WT and tet8 mutant. The characteristic enrichment of sphingolipid GIPCs provides valuable insights into the biogenesis and function of plant EVs.
A lipidomic map of Arabidopsis leaf extracellular vesicles (EVs) discloses compositions of major classes of lipids, including sphingolipids which are predominated by glycosylinositolphosphoceramides (GIPCs). Comparison to a tetraspanin knock-out mutant suggests a role of GIPCs in the EV production.
Quantum computers can efficiently solve classically intractable problems, such as the factorization of a large number
and the simulation of quantum many-body systems
. Universal quantum computation ...can be simplified by decomposing circuits into single- and two-qubit entangling gates
, but such decomposition is not necessarily efficient. It has been suggested that polynomial or exponential speedups can be obtained with global N-qubit (N greater than two) entangling gates
. Such global gates involve all-to-all connectivity, which emerges among trapped-ion qubits when using laser-driven collective motional modes
, and have been implemented for a single motional mode
. However, the single-mode approach is difficult to scale up because isolating single modes becomes challenging as the number of ions increases in a single crystal, and multi-mode schemes are scalable
but limited to pairwise gates
. Here we propose and implement a scalable scheme for realizing global entangling gates on multiple
Yb
ion qubits by coupling to multiple motional modes through modulated laser fields. Because such global gates require decoupling multiple modes and balancing all pairwise coupling strengths during the gate, we develop a system with fully independent control capability on each ion
. To demonstrate the usefulness and flexibility of these global gates, we generate a Greenberger-Horne-Zeilinger state with up to four qubits using a single global operation. Our approach realizes global entangling gates as scalable building blocks for universal quantum computation, motivating future research in scalable global methods for quantum information processing.
Although nonequilibrium work and fluctuation relations have been studied in detail within classical statistical physics, extending these results to open quantum systems has proven to be conceptually ...difficult. For systems that undergo decoherence but not dissipation, we argue that it is natural to define quantum work exactly as for isolated quantum systems, using the two-point measurement protocol. Complementing previous theoretical analysis using quantum channels, we show that the nonequilibrium work relation remains valid in this situation, and we test this assertion experimentally using a system engineered from a trapped ion, adding external noise to produce the effects of decoherence. Our experimental results reveal the work relation's validity over a variety of driving speeds, decoherence rates, and effective temperatures and represent the first confirmation of the work relation for evolution described by a non-unitary master equation.
Purpose
This paper aims to propose a liquid level sensor with a multi-S-bend plastic optical fiber.
Design/methodology/approach
The principle of liquid sensing used is based on the leakage of higher ...modes out of the fiber and repeated regeneration in the following bend sections. Therefore, a propagation loss was introduced in every bend section of the fiber with the loss depending on the refractive index of the environment.
Findings
Therefore, a continue shift in the liquid level can be detected by observing changes in the propagation loss of the fiber. The sensor features compactness and a flexible resolution.
Originality/value
Compared with the exited ones, the sensor has capability of continue liquid measurement and a greater measurement range.
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