Scientists say Darwins Tree of Life not the theory of everything

first_imgThe Tree of Life image that appeared in Darwin’s On the Origin of Species by Natural Selection, 1859. There is only one figure in On the Origin of Species, and that is a tree diagram. As Darwin’s model for the theory of evolution, he used the Tree of Life (TOL) to clearly and visually explain the interrelatedness of all living things, implying that from one common ancestor (the root) sprung branches, which produced smaller offshoots as genetic progeny, etc. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Scientists say Darwin’s ‘Tree of Life’ not the theory of everything (2007, March 12) retrieved 18 August 2019 from https://phys.org/news/2007-03-scientists-darwin-tree-life-theory.htmlcenter_img While such diverse methods might appear to obviously point to a more complex nonhierarchical evolutionary scheme, Doolittle and Bapteste explain that the TOL thinking persists due to confusion between the roles of “process” and “pattern.” The above methods are processes and are widely accepted by modern evolutionists, whereas the TOL is a pattern that, as Doolittle and Bapteste explain, has been ingrained in biologists’ minds from early education as a single, unifying model. As the researchers explain of the current biology scene, “We may be process pluralists, but we remain pattern monists.” If this combination of thinking seems to clash, Doolittle and Bapteste suggest that the Western philosophical tradition of thinking in universal patterns has caused biologists to cling to classification without realizing it. The authors point out that many algorithms used to study evolutionary hierarchies impose or extract the TOL structure due to their intrinsic design. TOL is a paradigm that has stuck. But Doolittle sees ways to alter this mentality.“Sure we can [re-train Western thinking]. That’s what ‘postmodernism’ is about,” he said. “I would agree that the need to classify might be built in, but the coupling of this practice to a specific theory about what classifications are ‘natural’ is surely not.As an alternative to the TOL, the scientists suggest that relationships among life forms may be represented by whatever model fits for a certain purpose, a certain taxonomic group, or a certain scale. In contrast to pattern monism, they call this belief “pattern pluralism.” While parts of evolution certainly are tree-like, other parts may be nets or webs or other complex models. Most importantly, however, there seems to be no “theory of everything” in evolution, no metanarrative to unify all life forms. “In 2006, our understanding of evolution at the molecular, population genetic, and ecological levels is rich and pluralistic in character,” the scientists conclude, “and does not require (or justify) a monistic view of the phylogenetic pattern.”As for any blow to Darwin’s ego, the scientists point out that he never wrote about reconstructing the tree in an attempt to relate every living thing, but rather used the model as a general guide. “I’d like to think he would adjust,” Doolittle said about Darwin. “After all, his theory was developed before there was any understanding of genetics and when bacteria were still believed to be spontaneously generated.”Citation: Doolittle, W. Ford, and Bapteste, Eric. “Pattern pluralism and the Tree of Life hypothesis.” PNAS, February 13, 2007, vol. 104, no. 7, 2043-2049.Copyright 2007 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. In this model, similarities between species reveal a common ancestor, and differences result from (and explain) Darwin’s main catalysts: competition and natural selection, which generate improvement in future generations. As a simile, the TOL served a vital purpose for introducing the theory of evolution to the community in an understandable way. Although there is no external evidence to support the idea that evolution is inclusively hierarchical, many evolutionists believe the TOL provides an accurate general representation of the history of life, which could potentially be completely reconstructed by knowing the relevant data. In recent times, however, a minority of biologists and evolutionists have questioned the accuracy of the TOL hypothesis, including W. Ford Doolittle and Eric Bapteste. In a recent paper in the Proceedings of the National Academy of Sciences, “Pattern Pluralism and the Tree of Life Hypothesis,” the scientists investigate the shortcomings of the TOL, as well as propose alternative models that would better explain how to classify the history of evolving life forms. Much of the initial concern over TOL was provoked by biologists studying the complex relationships among prokaryotes, the most primitive life forms that include bacteria and archaea. Prokaryotes have a much simpler DNA structure than eukaryotes (all other life forms). Because of this, prokaryotes often transfer their DNA via processes such as lateral gene transfer as opposed to vertical gene transfer (direct transmission form parent to progeny) which is the basis for the “phylogenetic” (evolutionary relatedness) TOL scheme. “Surely a tree is the right model for most multi-cellular animals and plants,” Doolittle explained to PhysOrg.com. “Thus the TOL is great for fossils and museums and dinosaurs and most of visible life, over the last billion years. But unicellular eukaryotes and prokaryotes represent the bulk of the biomass and diversity of life on earth, as well as the first two-thirds of its history.”In their paper, Doolittle and Bapteste highlight research that shows other causes of genetic modification, suggesting that evolutionary history is more complex than described by the TOL. For example, recombination, gene loss, duplication, and gene creation are a few of the processes whereby genes can be transferred within and between species, causing variation that’s not due to vertical transfer. These transfer methods give results that don’t fit on the TOL, including species that cannot be traced to a common ancestor. last_img read more

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Sharp Adds the D65U and D85U Series to Their AQUOS Line

first_img The D65U series includes the LC-52D65U 52-inch class that measures 52 1/32″ diagonal, LC-46D65U 46-inch class measures 45 63/64″ diagonal and LC-42D65U 42-inch class measures 42 1/64″ diagonal. The D65U series models are Energy Star compliant with very low power consumption. A new Power Saving Mode is available through the TV´s on-screen display menu; which enables active contrast and active backlight to reduce the energy consumption of the television while in use.The D65U AQUOS series provides a superior Full HD 1080p picture with outstanding performance, utilizing Sharp´s proprietary Advanced Super View (ASV) / Black TFT Panel with multi-pixel technology. The ASV/Black TFT Panel with Spectral Contrast Engine UD (Ultra Dark) provides high Dynamic Contrast Ratio and a pixel response time of 6 ms.The D65U series comes equipped with 5- HDMI inputs, 2- composite video inputs, 1- S-video, and a dedicated PC input with RS-232C for system control. The HDMI inputs feature version 1.3 with deep color, which adds compatibility with many high-end features such as enhanced colors and audio. They are also compatible with AQUOS Link, which enables convenient control of compatible devices.The D85U series offers the same superior quality picture in a 52, 46, and 42-inch package. The D85U series is also Energy Star compliant with very low power consumption, but utilizes 120Hz Fine Motion Enhanced technology. Other features include a 4ms response time, 10-bit Advanced Super View (ASV) / Black TFT Panel with Spectral Contrast Engine UD (Ultra Dark), 176-degree viewing angles, and five HDMI inputs.Sharp’s LC-42D65U is available now for $1,600. The LC-46D65U priced at $1,900 and LC-52D65U priced at $2,400 will be available in October. The LC-52D85U priced at $2,600 and LC-46D85U priced at $2,200 will be available in October. The LC-42D85U which is priced at $1,900 will be available a month later.Via: Electronic House and Engadget Sharp, a worldwide leader in flat panel LCD’s, expands their widescreen, full HD 1080p line of AQUOS LCD TVs with the attractive D65U and D85U series. Both the D65U and D85U feature a slim design and breathtaking realistic picture quality. This line of AQUOS LCD TV’s provides the ultimate home entertainment experience. Citation: Sharp Adds the D65U and D85U Series to Their AQUOS Line (2008, September 4) retrieved 18 August 2019 from https://phys.org/news/2008-09-sharp-d65u-d85u-series-aquos.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Image courtesy of Electronic Houselast_img read more

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Researchers find animals with bigger brains less prone to extinction

first_img More information: Amiel JJ, Tingley R, Shine R (2011) Smart Moves: Effects of Relative Brain Size on Establishment Success of Invasive Amphibians and Reptiles. PLoS ONE 6(4): e18277. doi:10.1371/journal.pone.0018277AbstractBrain size relative to body size varies considerably among animals, but the ecological consequences of that variation remain poorly understood. Plausibly, larger brains confer increased behavioural flexibility, and an ability to respond to novel challenges. In keeping with that hypothesis, successful invasive species of birds and mammals that flourish after translocation to a new area tend to have larger brains than do unsuccessful invaders. We found the same pattern in ectothermic terrestrial vertebrates. Brain size relative to body size was larger in species of amphibians and reptiles reported to be successful invaders, compared to species that failed to thrive after translocation to new sites. This pattern was found in six of seven global biogeographic realms; the exception (where relatively larger brains did not facilitate invasion success) was Australasia. Establishment success was also higher in amphibian and reptile families with larger relative brain sizes. Future work could usefully explore whether invasion success is differentially associated with enlargement of specific parts of the brain (as predicted by the functional role of the forebrain in promoting behavioural flexibility), or with a general size increase (suggesting that invasion success is facilitated by enhanced perceptual and motor skills, as well as cognitive ability).via Nature Citation: Researchers find animals with bigger brains less prone to extinction (2012, July 18) retrieved 18 August 2019 from https://phys.org/news/2012-07-animals-bigger-brains-prone-extinction.html Explore further (Phys.org) — Biological scientist Eric Abelson of Stanford University has been studying the link between survivability of a species over time and brain size relative to body mass, and has found that as a general rule, it appears that small mammals that have relatively large brains tend to be more likely to survive over long periods of time than those with smaller brains. He has presented his findings to a recent meeting of conservation scientists. Meanwhile, in an unrelated study, Joshua J. Amiel, Reid Tingley and Richard Shine of the University of Sydney, have found that amphibians, birds and reptiles with larger brains relative to body size released into a new environment tend to fare better than do those with smaller brains. They have had their paper on the topic published in the journal PLoS One. © 2012 Phys.org Journal information: PLoS ONE Big-brained birds survive better in nature Both studies are part of the overall body of research initiatives looking into the factors that contribute to the success of a species or conversely, which lead to their ultimate demise. Such studies help scientists better understand which species are most at risk in the modern era as more and more animals lose their natural habitat to human encroachment. Information gleaned from such research may help conservationists better determine where resources are best allocated.It would seem likely that the smartest species of animals would be the most likely to survive when the environment changes, and Abelson’s research has borne that out, but only in some circumstances. He looked at two groups of mammals, a small subset of mammals that lived from 40 million years ago on up to the present, and another small subset of those from the so-called modern age. Half of the first group eventually went extinct. In comparing brain to body size of all of those studied, he found that small mammals with relatively large brains were more likely to have survived from “palaeo” times up till now and those of the modern age were less likely to appear on the endangered list; but only if they were relatively small animals overall, i.e. less than 10 kg. For larger mammals it didn’t appear that larger brain sizes relative to their bodies helped them survive, likely due to other factors such as longer gestation periods, fewer offspring, and the need for more food.In the second study, the research team looked at a host of different reptiles, birds and amphibians that have been relocated over the years to save them from certain death as their natural environment changed. They found that those with large brain to body ratios sizes tended to be more likely to survive in their new homes.Such research is likely to become even more important in the years ahead as global warming causes unpredictable changes to environments all over the planet. More information about how animals respond should help conservation scientists figure out which of them at risk might best be helped. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. 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Water dimer captured inside a fullereneC70

first_img More information: Rui Zhang et al. Synthesis of a distinct water dimer inside fullerene C70, Nature Chemistry (2016). DOI: 10.1038/nchem.2464AbstractThe water dimer is an ideal chemical species with which to study hydrogen bonds. Owing to the equilibrium between the monomer and oligomer structure, however, selective generation and separation of a genuine water dimer has not yet been achieved. Here, we report a synthetic strategy that leads to the successful encapsulation of one or two water molecules inside fullerene C70. These endohedral C70 compounds offer the opportunity to study the intrinsic properties of a single water molecule without any hydrogen bonding, as well as an isolated water dimer with a single hydrogen bond between the two molecules. The unambiguously determined off-centre position of water in (H2O)[email protected] by X-ray diffraction provides insights into the formation of (H2O)[email protected] Subsequently, the 1H NMR spectroscopic measurements for (H2O)[email protected] confirmed the formation of a single hydrogen bond rapidly interchanging between the encapsulated water dimer. Our theoretical calculations revealed a peculiar cis-linear conformation of the dimer resulting from confinement effects inside C70. Water has some rather unique properties. For example, water has an exceptionally high melting and boiling point thanks to its intermolecular hydrogen bonding network. It is this bonding network that makes isolating two water molecules very difficult. Investigating a water dimer would allow researchers to gain further insight into water’s intermolecular bonding network. Furthermore, water dimers have been observed in atmospheric water vapor.Prior studies have successfully isolated a single water molecule within a fullerene-C60. Fullerenes are hollow carbon spheres whose interior is isolated from the surrounding environment. Researchers have isolated highly reactive species within a fullerene such as metals or a nitrogen atom. The interior cavity of the fullerene-C60 is 3.7Å in diameter, which is too small to house a water dimer so Rui Zhang, Michihisa Murata, Tomoko Aharen, Atsushi Wakamiya, Takafumi Shimoaka, Takeshi Hasegawa, and Yasujiro Murata from Kyoto University focused on fullerene-C70, which has an ellipsoid shape with a long diameter of 4.6 Å.Zhang, et al. used a technique, known as molecular surgery, to insert one and two water molecules into a fullerene-C70. The molecular surgical method involves making a “hole” in a fullerene-C70 via a chemical reaction, inserting the target molecules under extreme conditions, and then closing the hole to reform the C70 sphere. Zhang, et al. developed a novel way to open the fullerene-C70 cage.There are two reactive sites on the surface of a fullerene-C70, α and β bonds that are good candidates for alkene addition. While α bonds are more reactive, focusing the addition reaction on the β bonds yielded a larger pore size. Once Zhang, et al. achieved a sufficiently large pore size through sequential C=C cleavage, they then forced water into the fullerene cavity under high pressure (9,000 atm) and heat (120oC). They were able to restore the fullerene’s cage using a two-step process and isolated fullerene-C70 with a single water molecule from empty fullerene using HPLC. Proton NMR and atmospheric pressure chemical ionization mass spectrometry confirmed the presence of a single water molecule within the fullerene. X-ray diffraction studies indicated that the water molecule is off-center within the cage and that there is still pore space available for the possibility of an additional water molecule.Indeed, Zhang, et al. found a trace product that they isolated using HPLC. Mass spectrometry and NMR studies provided compelling evidence that this was a water dimer encapsulated by fullerene-C70. The dimer has a single hydrogen bond between and the two molecules adopted a different conformation (cis-linear) from water’s normal conformation (trans-linear). Additionally, infrared studies clearly distinguished the empty C70 from the C70 containing one water molecule and the C70 containing two water molecules, providing further insight into the differences between the three species. This research provides an excellent opportunity for further studies to understand this water’s unique conformation in a confined space, as well as the nature of the single hydrogen bond. Scientists build world’s smallest ‘water bottle’ Explore further Journal information: Nature Chemistry © 2016 Phys.orgcenter_img Structures of fullerene C60, C70. Credit: (c) Nature Chemistry (2016). DOI: 10.1038/nchem.2464 Citation: Water dimer captured inside a fullerene-C70 (2016, March 14) retrieved 18 August 2019 from https://phys.org/news/2016-03-dimer-captured-fullerene-c70.html (Phys.org)—Researchers from Kyoto University have, for the first time, isolated a water dimer. Using a technique known as molecular surgery, they encapsulated the dimer within a fullerene-C70 molecule. Their work appears in the recent issue of Nature Chemistry. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

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Phononmediated quantum state transfer and remote qubit entanglement

first_img (A) Qubit state swap via the acoustic channel, with control pulses shown on the left. (B) Acoustic entanglement. With Q1 initially in |e⟩, a control signal applied to G1 releases half a phonon to the channel, captured later by Q2. In (A) and (B), circles and squares are Q1 and Q2 excited-state populations measured simultaneously after a time t. (C and D) Expectation values of two-qubit Pauli operators (C) for the reconstructed Bell state density matrix (D) at t = 0.65 μs. In (C) and (D), solid lines indicate values expected for the ideal Bell state |Ψ⟩=(|eg⟩+|ge⟩)/2–√. In (A) to (D), dashed lines are simulation results including a finite transfer efficiency and qubit imperfections. Credit: Science, doi: 10.1126/science.aaw8415 Citation: Phonon-mediated quantum state transfer and remote qubit entanglement (2019, May 2) retrieved 18 August 2019 from https://phys.org/news/2019-05-phonon-mediated-quantum-state-remote-qubit.html , Physical Review Letters More information: A. Bienfait et al. Phonon-mediated quantum state transfer and remote qubit entanglement, Science (2019). DOI: 10.1126/science.aaw8415 Yu Chen et al. Qubit Architecture with High Coherence and Fast Tunable Coupling, Physical Review Letters (2014). DOI: 10.1103/PhysRevLett.113.220502 K. J. Satzinger et al. Quantum control of surface acoustic-wave phonons, Nature (2018). DOI: 10.1038/s41586-018-0719-5 Journal information: Science LEFT: Simplified circuit diagram, with the gray box indicating elements on the flipped lithium niobate chip. RIGHT: (A-B) Scanning electron micrographs detailing the IDT and Bragg mirrors. (C) Extracted qubit decay rate measured at maximum coupling. Decay is dominated by phonon emission from the IDT. Blue circles are extracted from an exponential decay fit; red dashed line is the predicted circuit model. Credit: Science, doi: 10.1126/science.aaw8415 Thereafter, the scientists demonstrated the interferometric nature of the one-qubit phonon emission and capture process. Since it is challenging to monitor the scheme for quantum entangling and mechanical superposition during quantum decoherence (quantum decay or loss of quantum behavior of particles), Bienfait et al prepared Q1 in a transition state to emit a half-phonon and captured it again with Q1 after one transit. The scientists defined capture as the time reversal of emission and predicted that the two half quanta will either interfere destructively to cause re-excitation of the qubit, or constructively for its total emission in the experimental setup. As predicted, they showed that when the reflected half phonon interfered constructively with the emitted half phonon stored in Q1—the total energy transferred in to the SAW resonator, whereas destructive interference resulted in qubit re-excitation. The scientists used a simulation to include channel loss and qubit dephasing, to replicate experimental observations and credited any mismatch of the simulation to imperfections in the system. In this way, Bienfait et al used the experimental acoustic communication channel to transfer quantum states and generate remote entanglement between the two qubits. For example, surface-acoustic wave (SAW) phonons are proposed as a universal medium to couple remote quantum systems. These phonons can also efficiently convert between microwave and optical frequencies, linking microwave qubits to optical photons. As a result, many proposals have followed experiments to show the coherent emission and detection of traveling SAW phonons by a superconducting qubit, with sound taking on the role of light. Scientists have used traveling SAW phonons to transfer electrons between quantum dots to shuttle transport single electrons, coupled to nitrogen-vacancy centers and even drive silicon carbide spins. In previous work, researchers had also engineered standing-wave SAW phonons coherently coupled to superconducting qubits for the on-demand creation, detection and control of quantum acoustic states. © 2019 Science X Network , Nature The scientists next experimentally showed the emission and capture of a traveling phonon employing a one-qubit, single-phonon “ping-pong” experiment using qubit Q1. In the experiment, they set coupler G1 to a maximum while turning the G2 coupler off to monitor the excited-state population (Pe) of Q1. They showed the emission took about 150 ns, after which Pe remained near zero during phonon transit in the experimental setup. After approximately 0.5 µs, Bienfait et al. were able to recapture the returning phonons with a capture efficiency of 67 percent. During successive transits, the scientists observed a geometric decrease in the capture efficiency, which they credited to losses within the acoustic channel. They then conducted quantum process tomography of the one-qubit release-and-catch operation by reconstructing the process matrix with time. The quantum process tomography technique is the most appropriate and efficient scheme to analyze quantum systems when two-body interactions are not naturally available. Explore furthercenter_img The researchers also demonstrated quantum swap between the two qubits, Q1 and Q2, using the setup. This was possible since the scientists could sequentially store up to three traveling phonons in the SAW resonator. The process had a high fidelity rate, and the scientists credited any deviations to acoustic losses. As before, they used the acoustic channel to generate remote quantum entanglement between Q1 and Q2 to create a Bell state. In this way, Bienfait et al. experimentally showed clear and compelling results for the controlled release and capture of travelling phonons into a confined Fabry-Pérot resonator, primarily limited by acoustic losses. They demonstrated that the emission and capture processes were not determined by the length of the resonator, so the same processes were applicable to a non-resonant acoustic device. In total, the scientists detailed processes to experimentally generate high fidelity entanglement between two qubits. These results will form a step forward to realize fundamental quantum communication protocols with phonons. Scientists connect quantum bits with sound over record distances Experimental device. (A to C) Micrograph of flip-chip assembled device (A), with two superconducting qubits (Q1 and Q2, blue), connected to two tunable couplers (G1 and G2, purple), fabricated on sapphire (B). These are connected via two overlaid inductors (green) to a SAW resonator (C), fabricated on lithium niobate. The SAW resonator comprises two Bragg mirrors (orange), spaced by 2 mm, defining a Fabry-Pérot acoustic cavity probed by an interdigitated transducer (red). The red and blue outlines in (A) represent the locations of (B) and (C), respectively. (D) Simplified circuit diagram, with the gray box indicating elements on the flipped lithium niobate chip. (E) Excited-state population Pe for qubit Q1, with coupler G1 set to maximum and G2 turned off. Q1 is prepared in |e⟩ using a π pulse, its frequency set to ωQ1 (vertical scale) for a time t (horizontal scale), before dispersive readout of its excited population Pe (28). Q1 relaxes owing to phonon emission via the IDT, and if its frequency is within the mirror stop band from 3.91 to 4.03 GHz, the emitted phonon is reflected and generates qubit excitation revivals at times τ (orange line) and 2τ. The inset shows the pulse sequence. (F) Measured qubit energy decay time T1 for ωQ,i/2π=3.95 GHz as a function of the coupler Josephson junction phase δi, showing the qubit emission can be considerably faster than the phonon transit time (orange line), for both Q1 (circles) and Q2 (squares). Credit: Science, doi: 10.1126/science.aaw8415 (A) Calibrated control pulses (inset) ensure the release of a time-symmetric phonon and its efficient capture. Circles represent the measured excited-state population of Q1 when interrupting the sequence after a time t. (B) Measured excited-state population of Q1 while sweeping the delay between the emission and capture control pulses, evidencing a population geometrically decreasing with the number of transits (gray line). (C) Quantum process tomography at the maximum efficiency point of (B), with a process fidelity F1=0.83±0.002. (I) stands for the identity operator and X, Y, and Z for the Pauli operators. In (A) to (C), dashed lines indicate the results of a master equation simulation including a finite transfer efficiency and qubit imperfections. Credit: Science, doi: 10.1126/science.aaw8415 , Science Advances The scientists facilitated phonon transfer from one superconducting qubit (artificial atom) to another and observed the quantum entanglement (quantum state of each particle that cannot be described independently of the state of the other) of the two qubits in an acoustic channel during the study. Bienfait et al. provided a new route to couple hybrid quantum solid-state systems using surface acoustic waves as ‘good vibrations’ in quantum communication for future phononic applications. Phonons, or more specifically, surface acoustic wave phonons, are proposed as a method to coherently couple distant solid-state quantum systems. For instance, individual phonons in a resonant structure can be controlled and detected using superconducting qubits (described as macroscopic, lithographically defined artificial atoms) to generate and measure complex, stationary phonon states coherently. In the present work, Bienfait et al. reported the deterministic emission and capture of traveling surface acoustic wave phonons to allow quantum entanglement of two superconducting qubits in an experimental setup. They used a 2 mm-long acoustic quantum communication channel in the experiments, which allowed an approximately 500-nanosecond delay line, to demonstrate the emission and recapture of phonons. The scientists observed quantum state transfer between the two superconducting qubits with an efficiency of 67 percent and using partial transfer of a phonon, they generated an entangled Bell pair with a fidelity of 84 percent. Electromagnetic waves have played a singular role as carriers of quantum information between distant quantum nodes for distributed quantum information processing. Previous quantum experiments have used microwave photons to demonstrate deterministic and probabilistic remote entanglement generation between superconducting qubits to reach entanglement fidelities ranging from 60 to 95 percent. For some solid-state quantum systems, such as electrostatically defined quantum dots or electronic spins, a quantum property of electrons (also known as spintronics), strong interactions with the host material have made acoustic vibrations (or phonons) a superior alternative compared to the photon candidates. Quantum information platforms are based on qubits that talk to each other and photons (optical and microwave) are the carrier of choice—to date, to transfer quantum states between qubits. However, in some solid-state systems, acoustic vibrational properties of the material themselves known as phonons can be advantageous. In a recent study published on Science Advances, B. Bienfait and colleagues at the interdisciplinary departments of Molecular Engineering, Physics and Materials Science in the U.S. described the deterministic emission and capture of travelling (itinerant) phonons through an acoustic communication channel, to allow phonon-based coherent transfer of quantum states. With Q1 initially prepared in |e⟩, a control signal on G1 releases and subsequently recaptures half a phonon to the resonator. Simultaneously, a 20-MHz detuning pulse of varying duration is applied to Q1 to change its phase by ∆ϕ. (A) Measured Q1 excited-state population when interrupting the sequence after a time t, with a phase difference ∆ϕ = 0 (squares) or π (circles). The inset shows the control sequence. (B) Q1 final state Pe(t=tf) for tf=0.65 μs as a function of the phase difference ∆ϕ between the half-photon and half-phonon. Circles are experimental points. Dashed lines are simulations based on an input-output theory model. Credit: Science, doi: 10.1126/science.aaw8415 Therefore, in the present work, Bienfait et al. used traveling (itinerant) SAW phonons to realize the transfer of quantum states between two superconducting qubits experimentally. In the acoustic part of the device, they used a SAW resonator with an effective Fabry-Pérot mirror spacing 2 mm, to generate a single-pass traveling phonon with a travel time of about 0.5 microseconds (µs). By design, coupling between the qubit and Fabry-Pérot mode in the system allowed the phonon to be completely injected into the acoustic channel. Bienfait et al. then coupled the resonator to two frequency-tunable superconducting “Xmon” qubits, Q1 and Q2 (where ‘Xmon qubits’ were first introduced by Barends et al), while controlling their coupling electronically using two other tunable couplers, G1 and G2. The scientists could switch each coupler from maximum coupling to off in a few nanoseconds to isolate the qubits. The scientists engineered the tunable couplers, qubits and their respective control and readout lines on a sapphire substrate while constructing the SAW resonator on a separate lithium niobate substrate. For the SAW resonator, they used two acoustic mirrors with two Bragg mirrors (dielectric mirrors) on each side of the central acoustic emitter-receiver setup. For the acoustic emitter, they used an interdigital transducer (IDT) connected to a common electrical port. The scientists applied an electric pulse to the IDT to form two symmetric SAW pulses, which traveled in opposite directions, reflecting off the mirrors to complete a round trip in 508 nanoseconds. Bienfait et al controlled the coupling of qubits to IDT, to facilitate time-domain shaped emission of traveling phonons in to the resonator. To characterize emission in the experiments, they excited the qubit first and monitored its excited-state population before taking the decaying state of excitation into account as a product of phonon emission. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

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When Delhi feasted like Europe

Quartet of European Delights, which is a part of the ongoing V4 Festival, had a cultural evening with European performers Csillagszemuek (Starry-Eyed) Dance Ensemble. The foot-tapping dances, the colourful attires and the music was a complete European treat as one could go back in time when folk music dominated central Europe.The festival brought together traditional culinary recipes, menus, lively central European music and a photo exhibition at the same event. Also Read – ‘Playing Jojo was emotionally exhausting’The Hungarian group, Csillagszemuek (Starry-Eyed) Dance Ensemble, a group of 24 young people performed the vibrant and lively folk dances from Hungary and Europe. It was a visual as well as a musical treat as the boys tapped their foot to the beat.Chefs from Hungary, Poland, Czech Republic and Slovakia were flown down to India for a special European food and breweries spread. At the bar there were nine different beer brands from the European country. Also Read – Leslie doing new comedy special with Netflix’I cooked the duck like they do in Poland and there is chicken on the platter and some beetroot stock,’ said the chef from Poland who had come to India specially for the event. Hungarian cuisines like Goulosh were also prepared. With more guests turning up than expected, the food was quickly savoured with wine and beer.The nine varieties of beer which were served had distinct flavours.And if you thought you missed it, there’s another chance as a special Hungarian Cuisine Day will be hosted at the Eros Hotel on 4 November. read more

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