The deep-ocean floor is the least explored ecosystem on the planet, despite covering more than 60% of the Earth surface. Largely unknown life in abyssal sediments, from benthic animals to microbes, helps to recycle and/or sequester the sinking (in)organic matter originating from pelagic communities that are numerically dominated by microscopic plankton. Benthic ecosystems thus underpin two major ecosystem services of planetary importance: the healthy functioning of ocean food-webs and the burial of carbon on geological timescales, both of which are critical regulators of the Earth climate. Researchers from the Norwegian Research Centre (NORCE), Bjerknes Centre for Climate research, the University of Geneva, as well as from the CNRS/Genoscope and IFREMER in France, have massively sequenced eukaryotic DNA contained in deep-sea sediments from all major oceanic basins, and compared these new data to existing global-scale plankton datasets from the sunlit and dark water column, obtained by the Tara Oceans and Malaspina circumglobal expeditions. This provides the first unified vision of the full ocean eukaryotic biodiversity, from the surface to the deep-ocean sediment, allowing marine ecological questions to be addressed for the first time at a global scale and across the three-dimensional space of the ocean, representing a major step towards “One Ocean ecology.”

“With nearly 1700 samples and two billion DNA sequences from the surface to the deep-ocean floor worldwide, high-throughput environmental genomics vastly expands our capacity to study and understand deep-sea biodiversity, its connection to the water masses above and to the global carbon cycle,” says Tristan Cordier, Researcher at NORCE and Bjerknes Centre for Climate Research, Norway, and lead author of the study.

What lives in this dark and hostile environment?

By comparing sediment DNA sequences with the ones from pelagic realms, it was possible to distinguish indigenous benthic organisms from sinking plankton that had reached the seafloor from the overlying water column. Results indicate that this benthic biodiversity could be three times larger than in the water masses above; and this diversity is composed of very different taxonomic groups that are mostly unknown.

“We compared our deep-sea benthic DNA sequences to all references sequences available for known eukaryotes. Our data indicates that nearly two third of this benthic diversity cannot be assigned to any known group, revealing a major gap in our knowledge of marine biodiversity,” says Jan Pawlowski, Professor at the Department of Genetics and Evolution of the University of Geneva and at the Institute of Oceanology of the Polish Academy of Sciences in Sopot.

What can plankton DNA in deep-sea sediments tell us?

Analysis of the abundance and composition of plankton DNA in deep-sea sediments confirmed that polar regions are hotspots of carbon sequestration. Moreover, the composition of the plankton DNA in sediments predicts the variation of the strength of the biological pump, an ecosystem process that transfer atmospheric carbon dioxide into the deep ocean, hence regulating the global climate.

“For the first time, we can understand which members of plankton communities are contributing most to the biological pump, arguably the most fundamental ecosystem processes in the oceans,” says Colomban de Vargas, Researcher at CNRS in Roscoff, France.

How will the deep-sea be impacted by global changes?

This genomic dataset represents the first consistent snapshot of whole eukaryotic diversity in the modern ocean. It provides a unique opportunity to reconstruct ancient oceans from the DNA contained in the cumulative sediment record, to assess how climate has impacted plankton and benthic communities in the past.

“Our data will not only address global-scale questions on the biodiversity, biogeography and connectivity of marine eukaryotes. It can also serve as a basis to reconstruct the past functioning of the biological pump from ancient sedimentary DNA archives. It would then inform on its future strength in a warmer ocean, which is key for modelling the future carbon cycle under climate change,” explains Tristan Cordier.

“Our study further demonstrates that deep-sea biodiversity research is of paramount importance. Huge numbers of unknown organisms inhabit ocean-floor sediments and must play a fundamental role in ecological and biogeochemical processes. A better knowledge of this rich diversity is crucial if we are to protect these vast, relatively pristine ecosystems from the impacts of possible future human incursions and understand the effects on it of climate change,” concludes Andrew J. Gooday, Emeritus Fellow at the National Oceanography Centre, Southampton, who was also involved in the research.

Now there is definitive, experimental proof that at the nanoscale, the notion of multiple thin materials with distinct vibrations no longer holds. If the materials are thin, their atoms arrange identically, so that their vibrations are similar and present everywhere. Such structural and vibrational coherency opens new avenues in materials design, which will lead to more energy efficient, low-power devices, novel material solutions to recycle and convert waste heat to electricity, and new ways to manipulate light with heat for advanced computing to power 6G wireless communication.

The discovery emerged from a long-term collaboration of scientists and engineers at seven universities and two U.S. Department of Energy national laboratories. Their paper, Emergent Interface Vibrational Structure of Oxide Superlattices, was published January 26 in Nature.

Eric Hoglund, a postdoctoral researcher at the University of Virginia School of Engineering and Applied Science, took point for the team. He earned his Ph.D. in materials science and engineering from UVA in May 2020 working with James M. Howe, Thomas Goodwin Digges Professor of materials science and engineering. After graduation, Hoglund continued working as a post-doctoral researcher with support from Howe and Patrick Hopkins, Whitney Stone Professor and professor of mechanical and aerospace engineering.

Hoglund’s success illustrates the purpose and potential of UVA’s Multifunctional Materials Integration Initiative, which encourages close collaboration among different researchers from different disciplines to study material performance from atoms to applications.

“The ability to visualize atomic vibrations and link them to functional properties and new device concepts, enabled by collaboration and co-advising in materials science and mechanical engineering, advances MMI’s mission,” Hopkins said.

Hoglund employed microscopy techniques to answer questions raised in experimental results Hopkins published in 2013, reporting on thermal conductivity of superlattices, which Hoglund likens to a Lego building block.

“You can achieve desired material properties by changing how different oxides couple to each other, how many times the oxides are layered and the thickness of each layer,” Hoglund said.

Hopkins expected the phonon to get resistance as it traveled through the lattice network, dissipating thermal energy at each interface of the oxide layers. Instead, thermal conductivity went up when the interfaces were really close together.

“This led us to believe that phonons can form a wave that exists across all subsequent materials, also known as a coherent effect,” Hopkins said. “We came up with an explanation that fit the conductivity measurements, but always felt this work was incomplete.”

“It turns out, when the interfaces become very close, the atomic arrangements unique to the material layer cease to exist,” Hoglund said. “The atom positions at the interfaces, and their vibrations, exist everywhere. This explains why nanoscale-spaced interfaces produce unique properties, different from a linear mixture of the adjoining materials.”

Hoglund collaborated with Jordan Hachtel, an R&D associate in the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory, to connect local atomic structure to vibrations using new generations of electron microscopes at UVA and Oak Ridge. Working with high-spatial-resolution spectroscopic data, they mapped interlayer vibrations across interfaces in a superlattice.

“That’s the major advance of the Nature paper,” Hopkins said. “We can see the position of atoms and their vibrations, this beautiful image of a phonon wave based on a certain pattern or type of atomic structure.”

The Collaborative Trek to Collective Success

The highly collaborative effort began in 2018 when Hoglund was sharing research plans to characterize atomic vibrations at interfaces in perovskite oxides.

“I was going to Oak Ridge to work with Jordan for a week, so Jim and Patrick suggested I take the superlattice samples and just see what we can see,” Hoglund recalled. “The experiments that Jordan and I did at Oak Ridge boosted our confidence in using superlattices to measure vibrations at the atomic or nano-scale.”

During one of his later trips to Tennessee, Hoglund met up with Joseph R. Matson, a Ph.D. student conducting related experiments at Vanderbilt University’s Nanophotonic Materials and Devices laboratory led by Joshua D. Caldwell, the Flowers Family Chancellor Faculty Fellow and associate professor of mechanical engineering and electrical engineering. Using Vanderbilt’s instruments, they conducted Fourier-transform infrared spectroscopy experiments to probe optical vibrations in the entire superlattice. These well-established macroscopic measurements validated Hoglund’s novel microscopy approach.

From these experiments, Hoglund deduced that the properties he cared about — thermal transport and infrared response — stemmed from the interface’s influence on the superlattice’s well-ordered framework of oxygen atoms. The oxygen atoms arrange themselves in an eight-sided structure called an octahedra, with a metal atom suspended inside. The interaction between oxygen and metal atoms causes the octahedra to rotate across the material structure. The oxygen and metal arrangements in this framework generate the unique vibrations and give rise to the material’s thermal and spectral properties.

Back at UVA, Hoglund’s chance conversation with Jon Ihlefeld, associate professor of materials science and engineering and electrical and computer engineering, brought additional members and expertise to the effort. Ihlefeld mentioned that researchers affiliated with Sandia National Laboratories, Thomas Beechem, associate professor of mechanical engineering at Purdue University, and Zachary T. Piontkowski, a senior member of Sandia’s technical staff, were also trying to explain the optical behavior of phonons and had likewise found the exact same oxide superlattices to be an ideal material for their study.

Coincidentally, Hopkins had an ongoing research collaboration with Beechem, albeit with other material systems. “Rather than competing, we agreed to work together and make this something bigger than either of us,” Hoglund said.

Beechem’s involvement had an added benefit, bringing Penn State physicist and materials scientist Roman Engel-Herbert and his student Ryan C. Haisimaier into the partnership to grow material samples for the microscopy experiments underway at UVA, Oak Ridge and Vanderbilt. Up to this point, Ramamoorthy Ramesh, University of California, Berkeley, professor of physics and materials science and engineering, and his Ph.D. students Ajay K. Yadav and Jayakanth Ravichandran were the growers on the team, providing samples to Hopkins’ ExSiTE research group.

“We realized we had all of this really neat experimental data connecting vibrations at atomic and macroscopic length scales, but all of our explanations were still somewhat conjectures that we could not prove absolutely without theory,” Hoglund said.

Hachtel reached out to Vanderbilt colleague Sokrates T. Pantelides, University Distinguished Professor of Physics and Engineering, William A. & Nancy F. McMinn professor of physics, and professor of electrical engineering. Pantelides and his research group members De-Liang Bao and Andrew O’Hara employed density functional theory to simulate atomic vibrations in a virtual material with a superlattice structure.

Their theoretical and computational methods supported exactly the results produced by Hoglund and other experimentalists on the team. The simulation also enabled the experimentalists to understand how every atom in the superlattice vibrates with high precision and how this was related to structure.

At this point, the team had 17 authors: three microscopists, four optical spectroscopists, three computational scientists, five growers and two material scientists. It was time, they thought, to share their findings with the scientific community at large.

An initial peer reviewer of their manuscript advised the team to establish a more direct, causal connection between material structure and material properties. “We measured some cool new phenomena making connections over multiple length scales that should affect material properties, but we had not yet convincingly demonstrated whether and how the known properties changed,” Hoglund said.

Two graduate students in Hopkins’ ExSiTE lab, senior scientist John Tomko and Ph.D. student Sara Makarem, helped provide the final proof. Tomko and Makarem probed the superlattices using infrared lasers and demonstrated that the structure controlled non-linear optical properties and the lifetime of phonons.

“When you send in a photon of one unit of energy, the superlattices double that unit of energy,” Hopkins said. “John and Sara built a new capability in our lab to measure this effect, which we express as the second harmonic generation efficiency of these superlattices.” Their contribution expands the ExSiTE lab capabilities to understand new light-phonon interactions.

“I think this will enable advanced materials discovery,” Hopkins said. “Scientists and engineers working with other classes of materials may now look for similar properties in their own studies. I fully expect we will find that these phonon waves, this coherent effect, exists in a lot of other materials.”

The long-standing collaboration continues. Hoglund is in his second year as a postdoctoral researcher, working with both Howe and Hopkins. Together with Pantelides, Hachtel and Ramesh, he expects they will have new and exciting atomic structure-vibration ideas to share in the near future.

The proteins, called METTL-3 and METTL-14, can alter the chemical structure of DNA — the molecular vault in cells that stores a person’s genetic information. This is a new understanding, said article senior author Yogesh Gupta, PhD, assistant professor of biochemistry at UT Health San Antonio’s Greehey Children’s Cancer Research Institute. For 27 years since the discovery of METTL-3 and -14, scientists believed that the proteins could only alter a separate molecule called RNA, but not DNA, he said.

RNA molecules, which float inside cells either reading out DNA instructions to make proteins or influencing this process indirectly, can form different shapes such as hairpins. Dr. Gupta, lead author; Shan Qi, a PhD student in the Gupta lab; and the team observed that RNA of a certain structure like a hairpin can act as a glue that binds to METTL-3 and -14, preventing it from changing DNA’s chemical structure.

“It is a desirable therapeutic target,” Dr. Gupta said. “By uncovering the DNA-altering function of METTL-3 and -14 and learning that it can be regulated by certain RNAs, we provided information that will help in drug discovery research.

“Our next step is to understand DNA, RNA and METTL-3 and -14 interaction so that we can identify the areas on the proteins for the purpose of drug development,” he said.

This work was supported by the Max and Minnie Tomerlin Voelcker Fund, the Cancer Prevention & Research Institute of Texas, the Institute for Integration of Medicine and Science/Clinical and Translational Science Award, the Greehey Children’s Cancer Research Institute, The University of Texas System and the National Institute of Allergy and Infectious Diseases (1R01AI161363).

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When arranged into a 2D structure (or quasi-2D structure with a few layers), defects in the crystal structure of Sn-based MHPs called “grain boundaries” hamper the mobility of charge carriers throughout the material. If used in a TFT, this phenomenon results in a large series resistance that ultimately degrades performance. In contrast, a TFT made using an Sn-based MHP arranged into a 3D structure faces a different yet still crippling problem. The extremely high carrier density of the 3D material causes the transistor to be permanently ON unless very high voltages are applied. Needless to say, this renders such a device useless for many applications.

Fortunately, a team of scientists from Tokyo Tech, Japan, have found a solution to these limitations. In a recent study published in Advanced Scienceand led by Assistant Professor Junghwan Kim and Honorary Professor Hideo Hosono, the researchers proposed a novel concept based on a hybrid structure for Sn-based MHPs, called the “2D/3D core-shell structure.” In this structure, 3D MHP cores are fully isolated from one another and connected only through short 2D MHP strips (or “shells”). This alternating arrangement solves both of the abovementioned drawbacks simultaneously. But how?

The trick to lowering the series resistance of 2D MHPs is to eliminate the carrier mobility problems at grain boundaries, which are caused by misalignments between the conductive octahedra of the perovskite. Thanks to the way in which the 3D cores connect to the 2D segments, these misalignments disappear and the series resistance is greatly lowered. As for the high carrier density of 3D MHPs, this problem is simply not present when using the 2D/3D core-shell structure. Since the 3D cores are isolated, their carrier density is no longer relevant; instead, the 2D segments act as a bottleneck and limit the effective carrier density of the overall material.

To demonstrate the effectiveness of this novel structure, the team fabricated a complementary metal-oxide-semiconductor (CMOS) inverter by combining 2D/3D TFTs with a standard indium gallium zinc oxide TFT. “Our device exhibited a high voltage gain of 200 V/V at a drain voltage of 20 V. This performance is the best reported so far for a CMOS inverter made using Sn-MHP TFTs,” highlights Prof. Kim.

The innovative 2D/3D structure presented in this study will help scientists worldwide take advantage of the attractive electronic properties of perovskites. Moreover, their approach is not limited to a narrow class of materials or device types. “The proposed strategy could be applied to various solution-derived semiconductor systems, opening doors to flexible and printable electronics,” says Prof. Kim.

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Most galaxies visible from Earth resemble a flat disk with a thickened center. They are therefore similar to the sports equipment of a discus thrower. According to the Standard Model of Cosmology, however, such disks should form rather rarely. This is because in the model, every galaxy is surrounded by a halo of dark matter. This halo is invisible, but exerts a strong gravitational pull on nearby galaxies due to its mass. “That’s why we keep seeing galaxies merging with each other in the model universe,” explains Prof. Dr. Pavel Kroupa of the Helmholtz Institute for Radiation and Nuclear Physics at the University of Bonn.

This crash has two effects, the physicist explains: “First, the galaxies penetrate in the process, destroying the disk shape. Second, it reduces the angular momentum of the new galaxy created by the merger.” Put simply, this greatly decreases its rotational speed. The rotating motion normally ensures that the centrifugal forces acting during this process cause a new disk to form. However, if the angular momentum is too small, a new disk will not form at all.

Large discrepancy between prediction and reality

In the current study, Kroupa’s doctoral student, Moritz Haslbauer, led an international research group to investigate the evolution of the universe using the latest supercomputer simulations. The calculations are based on the Standard Model of Cosmology; they show which galaxies should have formed by today if this theory were correct. The researchers then compared their results with what is currently probably the most accurate observational data of the real Universe visible from Earth.

“Here we encountered a significant discrepancy between prediction and reality,” Haslbauer says: “There are apparently significantly more flat disk galaxies than can be explained by theory.” However, the resolution of the simulations is limited even on today’s supercomputers. It may therefore be that the number of disk galaxies that would form in the Standard Model of Cosmology has been underestimated. “However, even if we take this effect into account, there remains a serious difference between theory and observation that cannot be remedied,” Haslbauer points out.

The situation is different for an alternative to the Standard Model, which dispenses with dark matter. According to the so-called MOND theory (the acronym stands for “MilgrOmiaN Dynamics), galaxies do not grow by merging with each other. Instead, they are formed from rotating gas clouds that become more and more condensed. In a MOND universe, galaxies also grow by absorbing gas from their surroundings. However, mergers of full-grown galaxies are rare in MOND. “Our research group in Bonn and Prague has uniquely developed the methods to do calculations in this alternative theory,” says Kroupa, who is also a member of the Transdisciplinary Research Units “Modelling” and “Matter” at the University of Bonn. “MOND’s predictions are consistent with what we actually see.”

Challenge for the Standard Model

However, the exact mechanisms of galaxy growth are not yet fully understood, even with MOND. Additionally, in MOND, Newton’s laws of gravity do not apply under certain circumstances, but need to be replaced by the correct ones. This would have far-reaching consequences for other areas of physics. “Nevertheless, the MOND theory solves all known extragalactic cosmological problems despite being originally formulated to address galaxies only,” says Dr. Indranil Banik, who was involved in this research. “Our study proves that young physicists today still have the opportunity to make significant contributions to fundamental physics,” Kroupa adds.

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The study led by Professor Dr. Ana J. Garcia-Saez (CECAD — Cluster of Excellence for Aging Research at the University of Cologne) and Junior Professor Dr. Katia Cosentino (CellNanOs — Center for Cellular Nanoanalytics at the Osnabrück University) has been published in the journal Molecular Cell under the title ‘The interplay between BAX and BAK tunes apoptotic pore growth to control mitochondrial DNA-mediated inflammation’.

Normally, the body initiates apoptosis — a form of programmed cell death — to get rid of damaged cells. Knowledge of how exactly this clean-up mechanism functions at the level of the molecules involved can make a significant contribution to the therapy of diseases. In cancer, for example, the cells are not systematically removed from the body, but continue to live and spread. Radiotherapy treatment is routinely used to kill cancer cells, but it induces inflammation in the body. Research is being carried out worldwide to find out how cancer therapies cause inflammation and how treatments can be less harmful to the body.

In this study, the research team from CECAD and CellNanOs focused on two proteins that are already known to be involved in cell death. BAX and BAK are the two proteins that regulate the cell death mechanism in mitochondria, the power-houses of the cell. Using high-resolution imaging techniques, the researchers were able to observe for the first time how dynamically BAX and BAK formed structures in mitochondria that influenced cell death and inflammation.

Due to their great similarity, BAX and BAK have so far been referred to as twin proteins. That they differ systematically in their mechanism of action is a new finding of this study. The research team was able to show that BAK proteins organize into smaller structures more quickly than BAX, and that the two proteins influence each other.

‘We could clearly observe under the microscope how both proteins interacted with each other to form a pore in the mitochondrion, so that the mitochondrial DNA exited through the pore to trigger inflammation,’ explained Andreas Jenner of the University of Cologne. This dynamic interplay of BAK and BAX proteins was previously unknown, and it regulates the formation of the pore and thus the amount of mitochondrial DNA released. This, in turn, determines whether an inflammatory response is triggered in the body.

‘The relative availability of BAX and BAK proteins in cells determines the growth of the pore and the rate at which mitochondrial DNA is released. Possibly, our findings open up new perspectives to control inflammation during cancer treatments,’ explained Katia Cosentino of the Osnabrück University.

‘Our results highlight how BAX and BAK contribute to cell death in different ways and suggest that these two proteins should be well balanced in therapeutic cancer treatments,’ said Ana J. Garcia-Saez of the University of Cologne.

However, such therapy does not yet exist. For now, further investigation is needed to determine whether additional molecules contribute to the dynamics of BAX and BAK pore formation and regulate pore growth and size.

Work for the study began at the IFIB (Interfaculty Institute of Biochemistry) in Tübingen and was completed at the CECAD Research Center, Institute of Genetics, in the Garcia-Saez laboratory in Cologne and at the Center for Cellular Nanoanalytics (CellNanOs) at the Osnabrück University.

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The new, modified charge pumping technique can detect single defects as small as the diameter of a hydrogen atom (one-tenth of a billionth of a meter) and can indicate where they’re located in the transistor. Researchers could also use the new capability to detect and manipulate a property in each electron known as quantum spin. The ability to manipulate individual spins has applications in both basic research and quantum engineering and computing.

Transistors act as electrical switches. In the on position, which represents the “1” of binary digital information, a designated amount of current flows from one side of a semiconductor to the other. In the off position, representing the “0” of binary logic, current ceases to flow.

Defects in a transistor can interfere with the reliable flow of current and significantly degrade the performance of transistors. These defects could be broken chemical bonds in the transistor material. Or they could be atomic impurities that trap electrons in the material. Scientists have devised several ways to categorize defects and minimize their impact, tailored to the structure of the transistor under study.

In the traditional design known as the metal oxide semiconductor field effect transistor (MOSFET), a metal electrode called the gate sits atop a thin insulating layer of silicon dioxide. Below the insulating layer lies the interface region that separates the insulating layer and the main body of the semiconductor. In a typical transistor, current travels through a narrow channel, only one billionth of a meter thick, that extends from the source, which lies on one side of the gate, to a “drain” on the other side. The gate controls the amount of current in the channel.

Charge pumping is a two-step process in which the examiner alternately pulses the gate with a positive test voltage, then a negative one. (The transistor does not act as an on/off switch during this testing mode.) In traditional charge pumping, the alternating voltage pulses are applied at a single, set frequency.

In the first step of the test, the positive voltage attracts or pumps electrons, which are negatively charged, to the boundary or interface between the gate’s insulating layer and the body of the transistor. Some of the pumped electrons become trapped in defects at the interface, but there are many electrons left over. In the second step, a negative voltage is applied, to rid the interface of the excess electrons, leaving only the trapped ones behind. The negative voltage also attracts positive charge carriers, known as “holes,” to the region, where they combine with electrons trapped in the defects. This activity generates a current proportional to the number of defects. The greater the output current, the larger the number of defects.

In the recent past, the current was indeed a reliable measure of defects. However, the insulating oxide layer in modern transistors is now so thin — just 10 to 20 hydrogen atoms wide — that an effect from the realm of quantum mechanics comes into play, confounding measurements using the traditional charge-pumping method.

According to quantum theory, electrons and other subatomic particles can never be truly trapped; there’s always some probability they will escape or “tunnel” out of an enclosure or boundary layer. The thinner the material, the higher the probability that electrons will escape, creating a tunneling current. As transistor dimensions shrank, the tunneling current leaking through the insulating oxide layer made it nearly impossible to detect defects with ordinary charge pumping. Scientists all but abandoned the technique.

NIST researchers James Ashton, Mark Anders and Jason Ryan have now found a way to salvage the technique so that it not only works for ultrathin transistor components but is also more sensitive, enabling scientists to record signals from a single defect. The solution arose when the scientists came to a key realization: The current that results from quantum tunneling remains virtually the same, regardless of the frequency at which charge pumping pulses the positive and negative voltages.

Armed with that knowledge, the team revised the charge pumping technique by alternately applying the method’s positive and negative voltages at two different frequencies rather than the single frequency used in the traditional method. Applying the voltages at two different frequencies gave the researchers two different output currents. By subtracting one output current from the other, the constant signal from the quantum tunneling current dropped out. With the confounding tunneling current eliminated, the researchers were able to detect defects in transistors with ultrasmall features. The researchers reported their development of the frequency-modulated charge pumping technique online in the Feb. 2 Applied Physics Letters.

“We’ve given charge pumping a new lease on life,” said Ashton.

“The modulated-frequency technique is now useful for looking at single interface defects, which gives engineers control of single electron charges in a very sensitive measurement scheme,” he added.

Since only one electron is involved, the output current is equal to multiples of the electron’s charge, a fundamental physics constant calculated by NIST and other institutions.

Because the method can detect single electrons, it may serve as a sensitive probe of an electron’s quantum spin. Modulated-frequency charge pumping may provide a valuable guide to scientists who are now exploring how electron spin might store and transfer information in a computer of the future. It may also prove useful in quantum metrology, as a potential new way of determining a quantum standard of electrical current.