11 research outputs found
Experimental test of the Jarzynski equality in a single spin-1 system using high-fidelity single-shot readouts
The Jarzynski equality (JE), which connects the equilibrium free energy with
non-equilibrium work statistics, plays a crucial role in quantum
thermodynamics. Although practical quantum systems are usually multi-level
systems, most tests of the JE were executed in two-level systems. A rigorous
test of the JE by directly measuring the work distribution of a physical
process in a high-dimensional quantum system remains elusive. Here, we report
an experimental test of the JE in a single spin-1 system. We realized
nondemolition projective measurement of this three-level system via cascading
high-fidelity single-shot readouts and directly measured the work distribution
utilizing the two-point measurement protocol. The validity of the JE was
verified from the non-adiabatic to adiabatic zone and under different effective
temperatures. Our work puts the JE on a solid experimental foundation and makes
the NV center system a mature toolbox to perform advanced experiments of
stochastic quantum thermodynamics
Experimental study on the principle of minimal work fluctuations
The central quantity in the celebrated quantum Jarzynski equality is
, where is work and is the inverse temperature. The
impact of quantum randomness on the fluctuations of and hence on
the predictive power of the Jarzynski estimator is an important problem.
Working on a single nitrogen-vacancy center in diamond and riding on an
implementation of two-point measurement of non-equilibrium work with
single-shot readout, we have conducted a direct experimental investigation of
the relationship between the fluctuations of and adiabaticity of
non-equilibrium work protocols. It is observed that adiabatic processes
minimize the variance of , thus verifying an early theoretical
concept, the so-called principle of minimal work fluctuations. Furthermore, it
is experimentally demonstrated that shortcuts-to-adiabaticity control can be
exploited to minimize the variance of in fast work protocols.
Our work should stimulate further experimental studies of quantum effects on
the bias and error in the estimates of free energy differences based on the
Jarzynski equality
The Bryopsis hypnoides Plastid Genome: Multimeric Forms and Complete Nucleotide Sequence
BACKGROUND: Bryopsis hypnoides Lamouroux is a siphonous green alga, and its extruded protoplasm can aggregate spontaneously in seawater and develop into mature individuals. The chloroplast of B. hypnoides is the biggest organelle in the cell and shows strong autonomy. To better understand this organelle, we sequenced and analyzed the chloroplast genome of this green alga. PRINCIPAL FINDINGS: A total of 111 functional genes, including 69 potential protein-coding genes, 5 ribosomal RNA genes, and 37 tRNA genes were identified. The genome size (153,429 bp), arrangement, and inverted-repeat (IR)-lacking structure of the B. hypnoides chloroplast DNA (cpDNA) closely resembles that of Chlorella vulgaris. Furthermore, our cytogenomic investigations using pulsed-field gel electrophoresis (PFGE) and southern blotting methods showed that the B. hypnoides cpDNA had multimeric forms, including monomer, dimer, trimer, tetramer, and even higher multimers, which is similar to the higher order organization observed previously for higher plant cpDNA. The relative amounts of the four multimeric cpDNA forms were estimated to be about 1, 1/2, 1/4, and 1/8 based on molecular hybridization analysis. Phylogenetic analyses based on a concatenated alignment of chloroplast protein sequences suggested that B. hypnoides is sister to all Chlorophyceae and this placement received moderate support. CONCLUSION: All of the results suggest that the autonomy of the chloroplasts of B. hypnoides has little to do with the size and gene content of the cpDNA, and the IR-lacking structure of the chloroplasts indirectly demonstrated that the multimeric molecules might result from the random cleavage and fusion of replication intermediates instead of recombinational events
Green synthesis of highly stable platinum nanoparticles stabilized by amino-terminated ionic liquid and its electrocatalysts for dioxygen reduction and methanol oxidation
Preparation of monodispersed platinum nanoparticles with average size 2.0Â nm stabilized by amino-terminated ionic liquid was demonstrated. The resulting platinum nanoparticles (Pt-IL) retained long-term stability without special protection. The Pt-IL nanoparticles exhibited high electrocatalytic activity toward reduction of oxygen and oxidation of methanol. Rotating disk electrode voltammetry and rotating ring-disk electrode voltammetry confirmed that the Pt-IL films could catalyze an almost four-electron reduction of dioxygen to water. Keywords: Platinum nanoparticles, Ionic liquids, Electrocatalysi
Experimental Study on Silty Seabed Liquefaction and Its Impact on Sediment Resuspension by Random Waves
Seabed liquefaction and sediment resuspension under wave loading are key issues in marine engineering, but are usually regarded as independent processes (instead of coexisting and interacting processes). Here, we analyzed random wave-induced seabed liquefaction and its impact on sediment resuspension using flume experiments. Results show that in a nonliquefaction scenario, excess pore pressure in the seabed oscillates with wave fluctuations, but pressure accumulation is low, while a consistent upward pressure gradient promotes sediment suspension. Wave-induced shear stress was the key driver of sediment resuspension in a nonliquefaction scenario. In the liquefied state, waves with different amplitudes differently responded to excess pore pressure; small-amplitude waves accumulated pressure, while large-amplitude waves dissipated it. Liquefied soil formed mud waves, creating elliptical motion along with random waves. Seabed liquefaction accelerated sediment resuspension in the following ways: reducing soil critical shear stress; forming seepage channels inside the seabed; forming mud waves, resulting in increased turbulent kinetic energy; dissipating excess pore pressure and releasing porewater, expelling fine-grained sediment from the liquefied soil. Our study reveals the variation in excess pore pressure in silty seabed under random waves and its effect on sediment resuspension, which is significant for understanding soil liquefaction and sediment movement of silt