scholarly journals Superdiffusion of quantized vortices uncovering scaling laws in quantum turbulence

2021 ◽  
Vol 118 (6) ◽  
pp. e2021957118
Author(s):  
Yuan Tang ◽  
Shiran Bao ◽  
Wei Guo
Keyword(s):  
Scaling Laws ◽  
Quantum Turbulence ◽  
Temporal Correlation ◽  
Quantized Vortices ◽  
Quantum Fluids ◽  
Future Research ◽  
Long Distance ◽  
Experimental Conditions ◽  
Tracer Particles ◽  
Bose Einstein

Generic scaling laws, such as Kolmogorov’s 5/3 law, are milestone achievements of turbulence research in classical fluids. For quantum fluids such as atomic Bose–Einstein condensates, superfluid helium, and superfluid neutron stars, turbulence can also exist in the presence of a chaotic tangle of evolving quantized vortex lines. However, due to the lack of suitable experimental tools to directly probe the vortex-tangle motion, so far little is known about possible scaling laws that characterize the velocity correlations and trajectory statistics of the vortices in quantum-fluid turbulence, i.e., quantum turbulence (QT). Acquiring such knowledge could greatly benefit the development of advanced statistical models of QT. Here we report an experiment where a tangle of vortices in superfluid 4He are decorated with solidified deuterium tracer particles. Under experimental conditions where these tracers follow the motion of the vortices, we observed an apparent superdiffusion of the vortices. Our analysis shows that this superdiffusion is not due to Lévy flights, i.e., long-distance hops that are known to be responsible for superdiffusion of random walkers. Instead, a previously unknown power-law scaling of the vortex–velocity temporal correlation is uncovered as the cause. This finding may motivate future research on hidden scaling laws in QT.

scholarly journals Entropy of a Turbulent Bose-Einstein Condensate

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 956 ◽  
Author(s):  
Lucas Madeira ◽  
Arnol Daniel García-Orozco ◽  
Francisco Ednilson Alves dos Santos ◽  
Vanderlei Salvador Bagnato
Keyword(s):  
Quantum Turbulence ◽  
Excitation Amplitude ◽  
Einstein Condensate ◽  
Quantum Fluids ◽  
Sudden Increase ◽  
Bose Einstein Condensate ◽  
Onset Of Turbulence ◽  
Bose Einstein ◽  
Distinct Features ◽  
Made In

Quantum turbulence deals with the phenomenon of turbulence in quantum fluids, such as superfluid helium and trapped Bose-Einstein condensates (BECs). Although much progress has been made in understanding quantum turbulence, several fundamental questions remain to be answered. In this work, we investigated the entropy of a trapped BEC in several regimes, including equilibrium, small excitations, the onset of turbulence, and a turbulent state. We considered the time evolution when the system is perturbed and let to evolve after the external excitation is turned off. We derived an expression for the entropy consistent with the accessible experimental data, which is, using the assumption that the momentum distribution is well-known. We related the excitation amplitude to different stages of the perturbed system, and we found distinct features of the entropy in each of them. In particular, we observed a sudden increase in the entropy following the establishment of a particle cascade. We argue that entropy and related quantities can be used to investigate and characterize quantum turbulence.

scholarly journals Nanoscale Real-Time Detection of Quantum Vortices at Millikelvin Temperatures

2020 ◽  
Author(s):  
Andrew Guthrie ◽  
Sergey Kafanov ◽  
Mark Noble ◽  
Yuri Pashkin ◽  
George Pickett ◽  
...  
Keyword(s):  
Real Time ◽  
Quantum Turbulence ◽  
Quantized Vortices ◽  
Quantum Fluids ◽  
Single Vortex ◽  
Quantum Vortices ◽  
The Real ◽  
Classical Counterpart ◽  
Wide Range ◽  
Real Time Detection

Abstract Since we still lack a theory of classical turbulence, attention has focused on the conceptually simpler turbulence in quantum fluids. Can such systems of identical singly-quantized vortices provide a physically accessible "toy model" of the classical counterpart? That said, we have hitherto lacked detectors capable of the real-time, non-invasive probing of the wide range of length scales involved in quantum turbulence. However, we demonstrate here the real-time detection of quantum vortices by a nanoscale resonant beam in superfluid 4He at 10 mK. The basic idea is that we can trap a single vortex along the length of a nanobeam and observe the transitions as a vortex is either trapped or released, which we observe through the shift in the resonant frequency of the beam. With a tuning fork source, we can control the ambient vorticity density and follow its influence on the vortex capture and release rates. But, most important, we show that these devices are capable of probing turbulence on the micron scale.

scholarly journals Quantum Turbulence in Quantum Gases

2020 ◽  
Vol 11 (1) ◽  
pp. 37-56 ◽  
Author(s):  
L. Madeira ◽  
M.A. Caracanhas ◽  
F.E.A. dos Santos ◽  
V.S. Bagnato
Keyword(s):  
Liquid Helium ◽  
Degrees Of Freedom ◽  
Quantum Turbulence ◽  
Quantum Gases ◽  
Quantum Fluids ◽  
Ultracold Gases ◽  
Fundamental Properties ◽  
Similarities And Differences ◽  
Points Of View ◽  
Bose Einstein

Turbulence is characterized by a large number of degrees of freedom, distributed over several length scales, that result in a disordered state of a fluid. The field of quantum turbulence deals with the manifestation of turbulence in quantum fluids, such as liquid helium and ultracold gases. We review, from both experimental and theoretical points of view, advances in quantum turbulence focusing on atomic Bose–Einstein condensates. We also explore the similarities and differences between quantum and classical turbulence. Last, we present challenges and possible directions for the field. We summarize questions that are being asked in recent works, which need to be answered in order to understand fundamental properties of quantum turbulence, and we provide some possible ways of investigating them.

scholarly journals Quantum storm in a cold cup

2021 ◽  
Vol 52 (3) ◽  
pp. 25-27
Author(s):  
Carlo F. Barenghi ◽  
Ladislav Skrbek
Keyword(s):  
Quantum Physics ◽  
Quantum Turbulence ◽  
Quantized Vortices ◽  
Quantum Fluids ◽  
Two Dimensional ◽  
Classical Physics

Quantum turbulence, which manifests itself via a tangle of quantized vortices, occurs in quantum fluids, whose properties depend on quantum physics rather than classical physics. Here we report on two limiting forms of quantum turbulence which have been identified and how two-dimensional turbulence, until recently a mathematical idealization, has become experimental reality.

scholarly journals Entropy of a Turbulent Bose-Einstein Condensate

2020 ◽  
Author(s):  
Lucas Madeira ◽  
Arnol Daniel García-Orozco ◽  
Francisco Ednilson Alves dos Santos ◽  
Vanderlei Salvador Bagnato
Keyword(s):  
Quantum Turbulence ◽  
Excitation Amplitude ◽  
Einstein Condensate ◽  
Quantum Fluids ◽  
Sudden Increase ◽  
Bose Einstein Condensate ◽  
Onset Of Turbulence ◽  
Bose Einstein ◽  
Distinct Features ◽  
Made In

Quantum turbulence deals with the phenomenon of turbulence in quantum fluids, such as superfluid helium and trapped Bose-Einstein condensates (BECs). Although much progress has been made in understanding quantum turbulence, several fundamental questions remain to be answered. In this work, we investigated the entropy of a trapped BEC in several regimes, including equilibrium, small excitations, the onset of turbulence, and a turbulent state. We considered the time evolution when the system is perturbed and let to evolve after the external excitation is turned off. We derived an expression for the entropy consistent with the accessible experimental data, that is, using the assumption that the momentum distribution is well-known. We related the excitation amplitude to different stages of the perturbed system, and we found distinct features of the entropy in each of them. In particular, we observed a sudden increase in the entropy following the establishment of a particle cascade. We argue that entropy and related quantities can be used to investigate and characterize quantum turbulence.

scholarly journals Validation of Reference Genes for Studying Different Abiotic Stresses in oat (Avena sativa L.) by RT-qPCR

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1272
Author(s):  
Judit Tajti ◽  
Magda Pál ◽  
Tibor Janda
Keyword(s):  
Gene Expression ◽  
Avena Sativa ◽  
Abiotic Stresses ◽  
Reference Genes ◽  
Nutritional Value ◽  
Tissue Type ◽  
Future Research ◽  
Experimental Conditions ◽  
Expression Studies ◽  
Gene Expression Studies

Oat (Avena sativa L.) is a widely cultivated cereal with high nutritional value and it is grown mainly in temperate regions. The number of studies dealing with gene expression changes in oat continues to increase, and to obtain reliable RT-qPCR results it is essential to establish and use reference genes with the least possible influence caused by experimental conditions. However, no detailed study has been conducted on reference genes in different tissues of oat under diverse abiotic stress conditions. In our work, nine candidate reference genes (ACT, TUB, CYP, GAPD, UBC, EF1, TBP, ADPR, PGD) were chosen and analysed by four statistical methods (GeNorm, Normfinder, BestKeeper, RefFinder). Samples were taken from two tissues (leaves and roots) of 13-day-old oat plants exposed to five abiotic stresses (drought, salt, heavy metal, low and high temperatures). ADPR was the top-rated reference gene for all samples, while different genes proved to be the most stable depending on tissue type and treatment combinations. TUB and EF1 were most affected by the treatments in general. Validation of reference genes was carried out by PAL expression analysis, which further confirmed their reliability. These results can contribute to reliable gene expression studies for future research in cultivated oat.

Archaic Origins of the Lowland Maya

2010 ◽  
Vol 21 (3) ◽  
pp. 312-352 ◽  
Author(s):  
Jon C. Lohse
Keyword(s):  
Cultural Change ◽  
New Technologies ◽  
Cultural Practices ◽  
Future Research ◽  
Late Archaic ◽  
Long Distance ◽  
Radiocarbon Data ◽  
Cultural Origins ◽  
Lines Of Evidence ◽  
Lowland Maya

The earliest Lowland Maya are commonly recognized by permanent architecture and the appearance of pottery. However, when other lines of evidence are considered, strong continuities with late Archaic populations can be seen. Reconciling these views relies on more than simply gathering more data. It is also necessary to consider the effect of decades of scholarship that defines the precolumbian Maya as “civilization” rather than considering the historical contexts of important transitions, such as the one that culminated with sedentism, the adoption of new technologies, and participation in long-distance exchange. The Archaic-to-Preclassic transition was relatively brief and largely obscured by the practices of establishing permanent dwellings. Nevertheless, this period must have been extremely dynamic and marked by significant cultural change, making it important to researchers interested in early Mesoamerica. Using three lines of evidence—subsistence, economy and technology, and stratigraphically controlled radiocarbon data—this article argues that the Lowland Maya had their cultural origins at least in the late Archaic and that the case for pottery before ca. 1000 B.C. remains uncertain. Future research is needed to determine precisely how far back in time certain cultural practices that characterize Preclassic and Classic Maya society can be documented.

scholarly journals The movement ecology of seagrasses

2014 ◽  
Vol 281 (1795) ◽  
pp. 20140878 ◽  
Author(s):  
Kathryn McMahon ◽  
Kor-jent van Dijk ◽  
Leonardo Ruiz-Montoya ◽  
Gary A. Kendrick ◽  
Siegfried L. Krauss ◽  
...  
Keyword(s):  
Life History ◽  
Clonal Growth ◽  
Movement Ecology ◽  
Future Research ◽  
The Novel ◽  
Long Distance ◽  
Spatial And Temporal Scales ◽  
Life History Stages ◽  
Research Areas ◽  
Time Movement

A movement ecology framework is applied to enhance our understanding of the causes, mechanisms and consequences of movement in seagrasses: marine, clonal, flowering plants. Four life-history stages of seagrasses can move: pollen, sexual propagules, vegetative fragments and the spread of individuals through clonal growth. Movement occurs on the water surface, in the water column, on or in the sediment, via animal vectors and through spreading clones. A capacity for long-distance dispersal and demographic connectivity over multiple timeframes is the novel feature of the movement ecology of seagrasses with significant evolutionary and ecological consequences. The space–time movement footprint of different life-history stages varies. For example, the distance moved by reproductive propagules and vegetative expansion via clonal growth is similar, but the timescales range exponentially, from hours to months or centuries to millennia, respectively. Consequently, environmental factors and key traits that interact to influence movement also operate on vastly different spatial and temporal scales. Six key future research areas have been identified.

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