Author(s): Jarryd J. Pla, Fahd A. Mohiyaddin, Kuan Y. Tan, Juan P. Dehollain, Rajib Rahman, Gerhard Klimeck, David N. Jamieson, Andrew S. Dzurak, and Andrea Morello The readout and manipulation of individual silicon nuclei has been achieved with a high…
Quantum Transport Evidence for the Three-Dimensional Dirac Semimetal Phase in Cd_{3}As_{2}
Author(s): L. P. He, X. C. Hong, J. K. Dong, J. Pan, Z. Zhang, J. Zhang, and S. Y. Li
Bulk quantum transport measurements of Cd3As2 provide further evidence that it is a 3D Dirac Semimetal – a quantum state of matter whose properties resemble a 3D analog of graphene.
[Phys. Rev. Lett. 113, 246402] Published Tue Dec 09, 2014
SU(2)×U(1) Gauge Invariance and the Shape of New Physics in Rare B Decays
Author(s): R. Alonso, B. Grinstein, and J. Martin Camalich An effective field theory for physics beyond the electroweak scale, where symmetries of the Standard Model are assumed to apply, provides model-independent constraints on new physics from the b…
Pattern Selection in Growing Tubular Tissues
Author(s): P. Ciarletta, V. Balbi, and E. Kuhl A model of soft biological tissue explains why wrinkles and folds form in tubular structures like the esophagus or the intestines.[Phys. Rev. Lett. 113, 248101] Published Tue Dec 09, 2014
Multi-GeV Electron Beams from Capillary-Discharge-Guided Subpetawatt Laser Pulses in the Self-Trapping Regime
Author(s): W. P. Leemans, A. J. Gonsalves, H.-S. Mao, K. Nakamura, C. Benedetti, C. B. Schroeder, Cs. Tóth, J. Daniels, D. E. Mittelberger, S. S. Bulanov, J.-L. Vay, C. G. R. Geddes, and E. Esarey
A laser-driven particle accelerator, delivering a beam of electrons with a record-breaking energy of 4.2 giga-electron-volts, could lead to compact x-ray lasers or high-energy colliders.
[Phys. Rev. Lett. 113, 245002] Published Mon Dec 08, 2014
Possible Role of Gamma Ray Bursts on Life Extinction in the Universe
Author(s): Tsvi Piran and Raul Jimenez Powerful stellar explosions may have caused mass extinctions on Earth and could also have prevented life from appearing on other planets until 5 billion years ago, and then only in the outskirts of galaxies.[Phys…
Electron-Vibration Interaction in the Presence of a Switchable Kondo Resonance Realized in a Molecular Junction
Author(s): D. Rakhmilevitch, R. Korytár, A. Bagrets, F. Evers, and O. Tal
The satellite peaks accompaning the zero-bias conductance peak in single molecule junctions of copper-phtalocyanide are experimentally shown to orignate from electron-phonon interactions.
[Phys. Rev. Lett. 113, 236603] Published Fri Dec 05, 2014
Electrical Spin Injection into High Mobility 2D Systems
Author(s): M. Oltscher, M. Ciorga, M. Utz, D. Schuh, D. Bougeard, and D. Weiss The injection of spins into a high-mobility two-dimensional electron gas is unexpectedly efficient, suggesting that new theories may be needed to describe spin transport in…
Probing the Axis Alignment of an Ultracold Spin-polarized Rb_{2} Molecule
Author(s): Markus Deiß, Björn Drews, Benjamin Deissler, and Johannes Hecker Denschlag
Cold molecules trapped in an optical lattice can be aligned by controlling their rotational quantum state.
[Phys. Rev. Lett. 113, 233004] Published Wed Dec 03, 2014
Reconstructing Folding Energy Landscape Profiles from Nonequilibrium Pulling Curves with an Inverse Weierstrass Integral Transform
Author(s): Megan C. Engel, Dustin B. Ritchie, Daniel A. N. Foster, Kevin S. D. Beach, and Michael T. Woodside
A new method is demonstrated for determining the free energy profile of a folded biopolymer from force-extension measurements.
[Phys. Rev. Lett. 113, 238104] Published Wed Dec 03, 2014
Universal Power Law Governing Pedestrian Interactions
Author(s): Ioannis Karamouzas, Brian Skinner, and Stephen J. Guy
A universal law for the interaction of pedestrians in a crowd, based on a walker’s ability to anticipate collisions, leads to accurate simulations of a variety of crowd conditions.
[Phys. Rev. Lett. 113, 238701] Published Tue Dec 02, 2014
Charge-Swapping Q Balls
Author(s): Edmund J. Copeland, Paul M. Saffin, and Shuang-Yong Zhou In nonlinear field theories with Q-ball (non-topological soliton) solutions, towers of composite Q-ball solutions exist, where positive and negative charges within a Q-ball can swap po…
Finite-Size Scaling as a Way to Probe Near-Criticality in Natural Swarms
Author(s): Alessandro Attanasi, Andrea Cavagna, Lorenzo Del Castello, Irene Giardina, Stefania Melillo, Leonardo Parisi, Oliver Pohl, Bruno Rossaro, Edward Shen, Edmondo Silvestri, and Massimiliano Viale The seemingly erratic motion of insects in a sw…
Photofragmentation Beam Splitters for Matter-Wave Interferometry
Author(s): Nadine Dörre, Jonas Rodewald, Philipp Geyer, Bernd von Issendorff, Philipp Haslinger, and Markus Arndt
A new technique in matter-wave interferometry using laser light to fragment molecules may open the door to interference demonstrations with large biomolecules or nanoclusters.
[Phys. Rev. Lett. 113, 233001] Published Mon Dec 01, 2014
Strongly Anisotropic Ballistic Magnetoresistance in Compact Three-Dimensional Semiconducting Nanoarchitectures
Author(s): Ching-Hao Chang, Jeroen van den Brink, and Carmine Ortix A 2D electron gas confined in nanotubes, formed by rolling up multilayer films of a non-magnetic semiconducting material, is predicted to exhibit strongly anisotropic magnetoresistance…
Tunable Charge and Spin Order in PrNiO_{3} Thin Films and Superlattices
Author(s): M. Hepting, M. Minola, A. Frano, G. Cristiani, G. Logvenov, E. Schierle, M. Wu, M. Bluschke, E. Weschke, H.-U. Habermeier, E. Benckiser, M. Le Tacon, and B. Keimer The metal-insulator transition in PrNiO3 is shown to arise from spin density …
Coherent Precession of an Individual 5/2 Spin
Author(s): M. Goryca, M. Koperski, P. Wojnar, T. Smoleński, T. Kazimierczuk, A. Golnik, and P. Kossacki
Researchers observed the precession of an individual spin-5/2 ion in a quantum dot, a system that could store multiple bits for quantum computing.
[Phys. Rev. Lett. 113, 227202] Published Tue Nov 25, 2014
High-Fidelity Preparation, Gates, Memory, and Readout of a Trapped-Ion Quantum Bit
Author(s): T. P. Harty, D. T. C. Allcock, C. J. Ballance, L. Guidoni, H. A. Janacek, N. M. Linke, D. N. Stacey, and D. M. Lucas
Qubits based on trapped ions can be prepared and manipulated with record-breaking accuracy, offering a promising scalable platform for quantum computing.
[Phys. Rev. Lett. 113, 220501] Published Mon Nov 24, 2014
Planck’s Quantum-Driven Integer Quantum Hall Effect in Chaos
Author(s): Yu Chen and Chushun Tian The kicked spin-1/2 rotor, a canonical chaotic system, is analogous to the integer quantum Hall effect.[Phys. Rev. Lett. 113, 216802] Published Fri Nov 21, 2014
Observation of an Excited B_{c}^{±} Meson State with the ATLAS Detector
Author(s): G. Aad et al. (ATLAS Collaboration)
The ATLAS Collaboration has observed a new excited state of the Bc± meson at 6842 MeV by reconstructing its decay. The mass and decay are consistent with QCD predictions for this excited state.
[Phys. Rev. Lett. 113, 212004] Published Fri Nov 21, 2014
Physics of Beer Tapping
Author(s): Javier Rodríguez-Rodríguez, Almudena Casado-Chacón, and Daniel Fuster
An investigation of the pub prank “beer tapping” provides a better understanding of gas-driven eruptions that occur in carbonated beverages, as well as in volcanic environments.
[Phys. Rev. Lett. 113, 214501] Published Thu Nov 20, 2014
Electronic Structure Basis for the Extraordinary Magnetoresistance in WTe2
Author(s): I. Pletikosić, Mazhar N. Ali, A. V. Fedorov, R. J. Cava, and T. Valla
A near perfect balance between electrons and holes explains why WTe2’s huge magnetoresistence doesn’t saturate at high fields, reaching 13 million percent at 60 tesla.
[Phys. Rev. Lett. 113, 216601] Published Wed Nov 19, 2014
Fixed-Point Quantum Search with an Optimal Number of Queries
Author(s): Theodore J. Yoder, Guang Hao Low, and Isaac L. Chuang
A well-known quantum search method, called Grover’s algorithm, has been modified to handle a wider variety of search problems.
[Phys. Rev. Lett. 113, 210501] Published Tue Nov 18, 2014
Improved Limit on a Temporal Variation of mp/me from Comparisons of Yb+ and Cs Atomic Clocks
Author(s): N. Huntemann, B. Lipphardt, Chr. Tamm, V. Gerginov, S. Weyers, and E. Peik Single-ion clocks yield new limits on how much the proton-to-electron mass ratio and the fine structure constant change over time.[Phys. Rev. Lett. 113, 210802] Publ…
Spacetime Curvature and the Higgs Stability During Inflation
Author(s): M. Herranen, T. Markkanen, S. Nurmi, and A. Rajantie Curvature corrections to the Standard Model effective potential explain why the universe did not become unstable during cosmological inflation.[Phys. Rev. Lett. 113, 211102] Published Mon …
Frequency Ratio of Two Optical Clock Transitions in Yb+171 and Constraints on the Time Variation of Fundamental Constants
Author(s): R. M. Godun, P. B. R. Nisbet-Jones, J. M. Jones, S. A. King, L. A. M. Johnson, H. S. Margolis, K. Szymaniec, S. N. Lea, K. Bongs, and P. Gill
Single-ion clocks yield new limits on how much the proton-to-electron mass ratio and the fine structure constant change over time.
[Phys. Rev. Lett. 113, 210801] Published Mon Nov 17, 2014
Toimus tippkeskuse ”Mesosüsteemid teoorias ja rakendustes” 3. konverents
13.novembril 2014.a. toimus Füüsika Instituudi uues majas, Physicumis, tippkeskuse ”Mesosüsteemid teoorias ja rakendustes” ( Centre of Excellence: Mesosystems: Theory and applications ) raames konverents. Kus esitati tulemusi tippkeskusesse kuuluvate Tartu Ülikooli, Tallinna Tehnikaülikooli ja Tallinna Ülikooli teadlaste poolt. Esinesi: V. Hizhnyakov “Vibrational solitons” A. Pishtshev “Oxygen mediated functionalization of yttrium trihydride” A. Šerman “Low-frequency quantum […]
Dynamic Control of the Polarization of Intense Laser Beams via Optical Wave Mixing in Plasmas
Author(s): P. Michel, L. Divol, D. Turnbull, and J. D. Moody
The polarization of an intense laser beam can theoretically be controlled by mixing it with a second beam in a plasma.
[Phys. Rev. Lett. 113, 205001] Published Fri Nov 14, 2014
New Exact Solution of the Relativistic Boltzmann Equation and its Hydrodynamic Limit
Author(s): Gabriel S. Denicol, Ulrich Heinz, Mauricio Martinez, Jorge Noronha, and Michael Strickland An exact solution of the relativistic Boltzmann equation with flow conditions relevant to heavy-ion collisions has been found.[Phys. Rev. Lett. 113, 2…
Anomalous Weak Values Are Proofs of Contextuality
Author(s): Matthew F. Pusey Weak measurements whose results exceed the largest eigenvalue of an operator manifest nonclassical behavior called contextuality.[Phys. Rev. Lett. 113, 200401] Published Wed Nov 12, 2014
Creation of Orbital Angular Momentum States with Chiral Polaritonic Lenses
Author(s): Robert Dall, Michael D. Fraser, Anton S. Desyatnikov, Guangyao Li, Sebastian Brodbeck, Martin Kamp, Christian Schneider, Sven Höfling, and Elena A. Ostrovskaya
A spiral pattern of light imparts angular momentum to a quantum condensate in a semiconductor.
[Phys. Rev. Lett. 113, 200404] Published Wed Nov 12, 2014
Two-Dimensional Directional Proton Emission in Dissociative Ionization of H2
Author(s): Xiaochun Gong, Peilun He, Qiying Song, Qinying Ji, Haifeng Pan, Jingxin Ding, Feng He, Heping Zeng, and Jian Wu The dynamics of hydrogen photo-dissociation are controlled on an attosecond time-scale using orthogonally polarized two-color ult…
Shear Banding of Colloidal Glasses: Observation of a Dynamic First-Order Transition
Author(s): V. Chikkadi, D. M. Miedema, M. T. Dang, B. Nienhuis, and P. Schall
A first-order jump is seen in the diffusion time scale of a sheared colloidal glass, as the applied shear field increases.
[Phys. Rev. Lett. 113, 208301] Published Wed Nov 12, 2014
Ultracold Dense Samples of Dipolar RbCs Molecules in the Rovibrational and Hyperfine Ground State
Author(s): Tetsu Takekoshi, Lukas Reichsöllner, Andreas Schindewolf, Jeremy M. Hutson, C. Ruth Le Sueur, Olivier Dulieu, Francesca Ferlaino, Rudolf Grimm, and Hanns-Christoph Nägerl
A step towards a collisionally stable quantum gas of dipolar molecules has been made by cooling a dense system of RbCs molecules to their electronic and rotational-vibrational ground state.
[Phys. Rev. Lett. 113, 205301] Published Wed Nov 12, 2014
Peltier Cooling of Fermionic Quantum Gases
Author(s): Ch. Grenier, A. Georges, and C. Kollath Simultaneous evaporative cooling of particles and holes would allow faster, deeper cooling of neutral Fermi gases. This new method could allow the gas to be cooled sufficiently for superfluidity and ul…
Experimental Realization of a One-Way Quantum Computer Algorithm Solving Simon’s Problem
Author(s): M. S. Tame, B. A. Bell, C. Di Franco, W. J. Wadsworth, and J. G. Rarity
A function finder called Simon’s algorithm has been experimentally tested on a prototype quantum computer for the first time.
[Phys. Rev. Lett. 113, 200501] Published Tue Nov 11, 2014
Search for a Dark Photon in e+e- Collisions at BaBar
Author(s): J. P. Lees et al. (BaBar Collaboration)
A search for a photonlike particle that could be related to dark matter has come up empty, putting new constraints on models that imagine a dark form of electromagnetism.
[Phys. Rev. Lett. 113, 201801] Published Mon Nov 10, 2014
Viscoelasticity Breaks the Symmetry of Impacting Jets
Author(s): H. Lhuissier, B. Néel, and L. Limat
A high-speed jet of certain fluids will form multiple wings, or archlike structures, when hitting a solid surface.
[Phys. Rev. Lett. 113, 194502] Published Fri Nov 07, 2014
Origin of the High Energy Cosmic Neutrino Background
Author(s): Shlomo Dado and Arnon Dar Collisions of ultrahigh energy cosmic rays within molecular clouds of star forming galaxies produce a diffuse background of very high energy neutrinos, consistent with that observed by the IceCube neutrino telescope…
Measurement-Device-Independent Quantum Key Distribution over 200 km
Author(s): Yan-Lin Tang, Hua-Lei Yin, Si-Jing Chen, Yang Liu, Wei-Jun Zhang, Xiao Jiang, Lu Zhang, Jian Wang, Li-Xing You, Jian-Yu Guan, Dong-Xu Yang, Zhen Wang, Hao Liang, Zhen Zhang, Nan Zhou, Xiongfeng Ma, Teng-Yun Chen, Qiang Zhang, and Jian-Wei Pa…
Statistical Diagnostics to Identify Galactic Foregrounds in B-Mode Maps
Author(s): Marc Kamionkowski and Ely D. Kovetz Ongoing searches for primordial gravitational waves have a new way to identify possible contaminations from cosmic dust.[Phys. Rev. Lett. 113, 191303] Published Thu Nov 06, 2014
Cooperative Lamb Shift in a Mesoscopic Atomic Array
Author(s): Z. Meir, O. Schwartz, E. Shahmoon, D. Oron, and R. Ozeri The roiling of the quantum vacuum tweaks the collective energy of far-apart ions.[Phys. Rev. Lett. 113, 193002] Published Wed Nov 05, 2014
High-Precision Test of Landauer’s Principle in a Feedback Trap
Author(s): Yonggun Jun, Momčilo Gavrilov, and John Bechhoefer
New experiments confirm the theoretical prediction of Rolf Landauer, that there is a lower bound on the minimum energy needed to perform a single computation, such as erasing a single bit of information.
[Phys. Rev. Lett. 113, 190601] Published Tue Nov 04, 2014
Landscape-Inversion Phase Transition in Dipolar Colloids: Tuning the Structure and Dynamics of 2D Crystals
Author(s): Ricard Alert, Jaume Casademunt, and Pietro Tierno A new first order phase transition is seen in magnetic colloidal crystals, when the energy landscape is completely inverted.[Phys. Rev. Lett. 113, 198301] Published Tue Nov 04, 2014
Magnetic Resonance Detection of Individual Proton Spins Using Quantum Reporters
Author(s): A. O. Sushkov, I. Lovchinsky, N. Chisholm, R. L. Walsworth, H. Park, and M. D. Lukin
An NMR scheme based on nitrogen vacancies in diamond images the spins of individual protons.
[Phys. Rev. Lett. 113, 197601] Published Mon Nov 03, 2014
Shear Modulus and Dilatancy Softening in Granular Packings above Jamming
Author(s): C. Coulais, A. Seguin, and O. Dauchot
Experiments on a model “soil” give new insight into the elasticity of nonlinear materials.
[Phys. Rev. Lett. 113, 198001] Published Mon Nov 03, 2014
Two-Dimensional Analysis of the Double-Resonant 2D Raman Mode in Bilayer Graphene
Author(s): Felix Herziger, Matteo Calandra, Paola Gava, Patrick May, Michele Lazzeri, Francesco Mauri, and Janina Maultzsch Raman spectroscopy, in particular the 2D Raman mode, is widely used to characterize bilayer graphene. The assumption that the 2D…
Lorentz Invariance in Chiral Kinetic Theory
Author(s): Jing-Yuan Chen, Dam T. Son, Mikhail A. Stephanov, Ho-Ung Yee, and Yi Yin
A kinetic theory, with explicit Lorentz invariance, is derived for chiral fermions in an external electromagnetic field. This theory provides the correct form for the chiral vortical effect — the appearance of a current in a system undergoing rotation.
[Phys. Rev. Lett. 113, 182302] Published Thu Oct 30, 2014
Indications of a Late-Time Interaction in the Dark Sector
Author(s): Valentina Salvatelli, Najla Said, Marco Bruni, Alessandro Melchiorri, and David Wands Discrepancies between different cosmological datasets could indicate interactions between dark matter and dark energy that occurred late in cosmological ev…
Frequency Comb Generation in Superconducting Resonators
Author(s): R. P. Erickson, M. R. Vissers, M. Sandberg, S. R. Jefferts, and D. P. Pappas
Superconducting niobium-titanium nitride resonators are used to generate multi-octave frequency combs in the microwave regime.
[Phys. Rev. Lett. 113, 187002] Published Thu Oct 30, 2014
Identification of a Gravitational Arrow of Time
Author(s): Julian Barbour, Tim Koslowski, and Flavio Mercati Masses evolving under Newtonian gravity have a preferred direction of time without special initial conditions.[Phys. Rev. Lett. 113, 181101] Published Wed Oct 29, 2014
Local to Extended Transitions of Resonant Defect Modes
Author(s): Joseph Lydon, Marc Serra-Garcia, and Chiara Daraio A linear chain of beads exhibits localized vibrational states when a defect is introduced into the chain. If the defect is resonant, the length of chain involved in this localized excitation…
Terasaki Spiral Ramps in the Rough Endoplasmic Reticulum
Author(s): Jemal Guven, Greg Huber, and Dulce María Valencia
A model for the fundamental building blocks of fluid membranes addresses how chiral stacking occurs in the endoplasmic reticulum, an essential cellular organelle.
[Phys. Rev. Lett. 113, 188101] Published Tue Oct 28, 2014
Programmable Mechanical Metamaterials
Author(s): Bastiaan Florijn, Corentin Coulais, and Martin van Hecke Squeezing a holey rubber slab changes its stiffness over a wide range in the direction perpendicular to the squeeze.[Phys. Rev. Lett. 113, 175503] Published Fri Oct 24, 2014
Mechanism for Thermal Relic Dark Matter of Strongly Interacting Massive Particles
Author(s): Yonit Hochberg, Eric Kuflik, Tomer Volansky, and Jay G. Wacker Strongly interacting light dark matter could provide a mechanism for achieving thermal relic dark matter abundances via inelastic processes at freezeout. This addresses outstandi…
Nonlinear Interaction between Single Photons
Author(s): T. Guerreiro, A. Martin, B. Sanguinetti, J. S. Pelc, C. Langrock, M. M. Fejer, N. Gisin, H. Zbinden, N. Sangouard, and R. T. Thew
The interaction between two individual photons in a nonlinear optical waveguide offers new possibilities for quantum information processing.
[Phys. Rev. Lett. 113, 173601] Published Wed Oct 22, 2014
Artificial Tribotactic Microscopic Walkers: Walking Based on Friction Gradients
Author(s): Joshua P. Steimel, Juan L. Aragones, and Alfredo Alexander-Katz
Pairs of micrometer-sized magnetic beads could “hunt” for chemicals by sensing changes in surface friction.
[Phys. Rev. Lett. 113, 178101] Published Wed Oct 22, 2014
Phonon Localization by Mass Disorder in Dense Hydrogen-Deuterium Binary Alloy
Author(s): Ross T. Howie, Ioan B. Magdău, Alexander F. Goncharov, Graeme J. Ackland, and Eugene Gregoryanz
Localized vibration phonon modes are observed in a dense hydrogen-deuterium mixture, due to mass distribution disorder from the different isotope masses in the mixture.
[Phys. Rev. Lett. 113, 175501] Published Tue Oct 21, 2014
Gravity Driven Instability in Elastic Solid Layers
Author(s): Serge Mora, Ty Phou, Jean-Marc Fromental, and Yves Pomeau A new Rayleigh-Taylor-like instability is seen in elastic gel materials, where the instability is driven by gravity.[Phys. Rev. Lett. 113, 178301] Published Tue Oct 21, 2014
In-Plane Magnetoresistance Obeys Kohler’s Rule in the Pseudogap Phase of Cuprate Superconductors
Author(s): M. K. Chan, M. J. Veit, C. J. Dorow, Y. Ge, Y. Li, W. Tabis, Y. Tang, X. Zhao, N. Barišić, and M. Greven
Kohler’s rule – that a metal’s resistivity in an applied magnetic field exhibits scaling behavior – is shown to be universally valid for the pseudogap phase of cuprate superconductors, if disorder and extrinsic influences are taken into account.
[Phys. Rev. Lett. 113, 177005] Published Tue Oct 21, 2014
Detection of Up-converted Persistent Luminescence in the Near Infrared Emitted by the Zn3Ga2GeO8:Cr3+, Yb3+, Er3+ Phosphor
Author(s): Feng Liu, Yanjie Liang, and Zhengwei Pan Persistent luminescence, lasting more than 24 hours, is generated in a new phosphor compound via an upconversion process.[Phys. Rev. Lett. 113, 177401] Published Tue Oct 21, 2014
Strong Constraints on Sub-GeV Dark Sectors from SLAC Beam Dump E137
Author(s): Brian Batell, Rouven Essig, and Ze’ev Surujon
Using 30 year old electron beam-dump data, stringent new constraints are placed on the parameter space of dark photons – recently proposed hypothetical force carriers between dark matter particles.
[Phys. Rev. Lett. 113, 171802] Published Tue Oct 21, 2014
Scattering of Massless Particles in Arbitrary Dimensions
Author(s): Freddy Cachazo, Song He, and Ellis Ye Yuan A new formula for the scattering of massless particles may simplify predictions and analyses of LHC experiments and shed new light on quantum gravity theories.[Phys. Rev. Lett. 113, 171601] Publish…
Classical Dynamical Localization
Author(s): Italo Guarneri, Giulio Casati, and Volker Karle
Features thought to be unique to quantum dynamical systems, such as localization of momentum, are found in a classical kicked rotor – where particles move in a ring and are ‘kicked’ periodically by an external field that changes the particle’s momentum.
[Phys. Rev. Lett. 113, 174101] Published Mon Oct 20, 2014
Quantum Data Compression of a Qubit Ensemble
Author(s): Lee A. Rozema, Dylan H. Mahler, Alex Hayat, Peter S. Turner, and Aephraim M. Steinberg A technique that packs the full content of three bits of quantum information into two may be a space saver for quantum computers.[Phys. Rev. Lett. 113, 1…
Trion-Induced Negative Photoconductivity in Monolayer MoS2
Author(s): C. H. Lui, A. J. Frenzel, D. V. Pilon, Y.-H. Lee, X. Ling, G. M. Akselrod, J. Kong, and N. Gedik
Ultrafast optical excitation of doped MoS2 causes a pronounced transient decrease in its conductivity, due to strong many-body interactions in the material that convert the 2D electron gas into a trion gas.
[Phys. Rev. Lett. 113, 166801] Published Thu Oct 16, 2014
Solvable Relativistic Hydrogenlike System in Supersymmetric Yang-Mills Theory
Author(s): Simon Caron-Huot and Johannes M. Henn A relativistic quantum field theory extension to the classical Kepler problem provides a new method to compute the bound states of massive W bosons in planar N=4 super Yang-Mills.[Phys. Rev. Lett. 113, 1…
New Classes of Systematic Effects in Gas Spin Comagnetometers
Author(s): D. Sheng, A. Kabcenell, and M. V. Romalis
Progress has been made in understanding systematic effects from thermal and magnetic field gradients on comagnetometers – devices that compare the nuclear spin procession of two atomic species.
[Phys. Rev. Lett. 113, 163002] Published Thu Oct 16, 2014
Fractional Angular Momentum in Cold-Atom Systems
Author(s): Yuhe Zhang, G. J. Sreejith, N. D. Gemelke, and J. K. Jain
A method is proposed that would allow fractional statistics to be measured experimentally using a pair of atoms immersed in a specifically tailored quantum many-body state.
[Phys. Rev. Lett. 113, 160404] Published Thu Oct 16, 2014
Reversing the Temporal Envelope of a Heralded Single Photon using a Cavity
Author(s): Bharath Srivathsan, Gurpreet Kaur Gulati, Alessandro Cerè, Brenda Chng, and Christian Kurtsiefer
The temporal pulse shape of a single photon can be engineered, from an exponential decay to an exponential rise, using a Fabry-Perot optical cavity. This ‘shaping’ would make it easier to couple photons to atoms in a cavity.
[Phys. Rev. Lett. 113, 163601] Published Wed Oct 15, 2014
Eight Types of Symmetrically Distinct Vectorlike Physical Quantities
Author(s): J. Hlinka The family of vector-like quantities is expanded from four to eight using symmetry arguments. These new vectors may be useful for describing systems including chiral objects, topological defects, or magnetic vortices.[Phys. Rev. Le…
Observation of Overlapping Spin-1 and Spin-3 D[over ¯]^{0}K^{-} Resonances at Mass 2.86 GeV/c^{2}
Author(s): R. Aaij et al. (LHCb Collaboration) The LHCb collaboration has observed the first spin-3 resonance containing a heavy quark produced in the decay of the bottom-hadron Bs0.[Phys. Rev. Lett. 113, 162001] Published Tue Oct 14, 2014
Kõverjooneliselt levivad Airy valguskuulid
Andreas Valdmann, Peeter Piksarv, Heli Valtna-Lukner, Peeter Saari TÜ Füüsika Instituut, Riia 142, Tartu 51014, Eesti Difraksioon on nähtus, mis alates valguse lainemudeli abil seletuse saamist on ootuspärane ja lausa paratamatuna näiv. Näiteks on difraktsioon põhjuseks, miks Maalt Kuu poole suunatud peenikese laserkiire läbimõõt kasvab teel sihtmärgini kilomeetritega mõõdetavaks, hoolimata sellest, kui hästi on laser […]
Bounds on Invisible Higgs Boson Decays Extracted from LHC tt¯H Production Data
Author(s): Ning Zhou, Zepyoor Khechadoorian, Daniel Whiteson, and Tim M. P. Tait
A reanalysis of LHC data from a supersymmetry search provides new constraints on the Higgs branching ratio to invisible particles, which are possibly related to dark matter.
[Phys. Rev. Lett. 113, 151801] Published Fri Oct 10, 2014
Strangeness Suppression of qq¯ Creation Observed in Exclusive Reactions
Author(s): M. D. Mestayer et al. (CLAS Collaboration)
Strange quark–anti-quark pairs are less likely to be produced in hadronic collisions than their light quark counterparts, providing insight into color confinement in QCD.
[Phys. Rev. Lett. 113, 152004] Published Fri Oct 10, 2014
Galactic Center Gamma-Ray Excess from Dark Matter Annihilation: Is There a Black Hole Spike?
Author(s): Brian D. Fields, Stuart L. Shapiro, and Jessie Shelton
Simple dark matter and astrophysical models can’t explain a gamma-ray signal from our Galaxy’s center.
[Phys. Rev. Lett. 113, 151302] Published Thu Oct 09, 2014
MoS2: Choice Substrate for Accessing and Tuning the Electronic Properties of Graphene
Author(s): Chih-Pin Lu, Guohong Li, K. Watanabe, T. Taniguchi, and Eva Y. Andrei
Molybdenum disulfide may provide an ideal substrate for supporting graphene.
[Phys. Rev. Lett. 113, 156804] Published Thu Oct 09, 2014
Fotoonika päev 2014
21.oktoobril 2014 tähistame esmakordselt Eestis Fotoonika päeva, kui ootame ootame kõiki teaduse- ja tehnoloogiahuvilisi TÜ Physicumi, kus toimuvad huviloengud, demonstratsioonkatsed ning ringkäigud. Sõna „fotoonika“ saadakse sõnast footon, mis omakorda on valguse osake. Fotoonika hõlmab laiemas tähenduses kõiki valguse manipuleerimist kasutavaid tehnilisi lahendusi, mille hulka kuuluvad näiteks teemad nagu LED-valgustus, kaasaegne päikesepaneelide tehnoloogia, laserid, sensorid, optilised […]
Catalytic Coherence
Author(s): Johan Åberg
A scheme is proposed to perform a unitary operation on a multi-level system, without degrading the coherence of the external system.
[Phys. Rev. Lett. 113, 150402] Published Tue Oct 07, 2014
Creating High-Harmonic Beams with Controlled Orbital Angular Momentum
Author(s): Genevieve Gariepy, Jonathan Leach, Kyung Taec Kim, T. J. Hammond, E. Frumker, Robert W. Boyd, and P. B. Corkum
A laser field carrying orbital angular momentum can drive nonlinear high harmonic generation in a gas, potentially forming an extreme ultraviolet beam having applications in molecular scale microscopy.
[Phys. Rev. Lett. 113, 153901] Published Tue Oct 07, 2014
Eile avati pidulikult Physicum
25. augustil avati Tartus Maarjamõisa teaduslinnakus pidulikult Ida-Euroopa kaasaegseim füüsikakeskus Physicum. Enam kui 16 miljonit eurot maksnud ehitus algas 2012. aasta juunis. Hoolimata vihmast oli hoone avamist vaatama tulnud palju uudishimulikke. Avatud ustega majas toimusid ekskursioonid ning tehti teadusteatrit. Suuremates auditooriumides peeti kõnesid ning näidati filme. Lapsed said osaleda töötubades. Õhtu edenedes mängis tantsuks bänd. […]
TÜ Füüsika Instituudi uue maja kerkimine
Selles videos on näeb TÜ Füüsika Instituudi uue hoone kerkimist Tartus, Ravila 14C. Maja avamine toimub 25.08.2014.
Uus nähtamatuks tegev seade töötab hajutavas keskkonnas
Saksa teadlased leiutasid uue nn nähtamatuks tegeva mantli, mis varjab objekte hajutavas keskkonnas, näiteks sogases vedelikus. Sama tehnoloogiat kasutades on tehtud ka mantleid, mis varjavad objekte kuumuse eest. Kuigi sellise seadme võimalikud rakendused on piiratud, võib teadlaste sõnul kasutada seda näiteks esteetilise kuid vargakindla klaasi valmistamisel. Nähtamatuks tegev mantel töötab, juhtides valguse objekti ümbert mööda […]
Laser jäljendab valguse abil bioloogilisi neuroneid
Õhukestest pooljuhi kihtidest valmistatud pisike laser funktsioneerib täpselt nagu bioloogiline neuron, leidis grupp prantsuse füüsikuid. Teadlastel õnnestus näidata, et nende ,,mikrosammastest” (“micropillar”) laser kiirgab valgust kohe, kui selle sisend muutub vaid minimaalselt – just nagu neuron. Järjestikused kiirgamised peavad lisaks olema üksteisest ajaliselt eraldatud, mis on samuti bioloogiliste neuronite üheks olulisimaks omaduseks. Inimaju koosneb ligikaudu […]
Uued tugevad superkondensaatorid
Ameerika Ühendriikide teadlased töötasid hiljuti välja tahkiselise superkondensaatori, mis on võimeline töötama ka sellele mõjuvate suurte jõudude ja vibratsioonide korral. Erinevalt traditsioonilistest superkondensaatoritest, ei delamineeru antud seade sellele mõjuvate suurte jõudude korral. See uus seade võib viia mitmete praktiliste rakendusteni, seehulgas lihtsalt efektiivsematest seadmetest kuni taastuvenergia salvestamiseni. Erinevalt akudest, mis töötavad tänu keemilistele reaktsioonidele, salvestavad […]
Kasvuhoonegaasi CO2 kasutamine plastide materjalina.
Leverkusen, 14. mai 2014 – Kasvuhoonegaasi süsinikdioksiidi võib kasutada plastide peamise materjalina. Pärast edukat katsefaasi ja paljutõotavat turuanalüüsi plaanib Bayer MaterialScience oma Dormageni tootmiskohas investeerida 15 miljonit eurot tootmisliini ehitamisse, mis hakkab kõrgkvaliteetse vahtpolüuretaani prekursori tootmiseks kasutama süsihappegaasi. Liini keskmine aastane tootmisvõimsus on 5000 tonni. Loataotlus esitatakse Kölni kohalikule omavalitsusele järgmise paari nädala jooksul. Projekti […]
ESA at ILA 2016
The space pavilion will feature the wealth of ESA and German national programmes across all space domains, focusing on recent mission results and upcoming launches.
ESA at ILA 2016
The space pavilion will feature the wealth of ESA and German national programmes across all space domains, focusing on recent mission results and upcoming launches.
Kas libisev liiv aitas egiptlastel püramiide ehitada?
Vana-Egiptuse kolossaalsete monumentide ehitajad võisid lisada kõrbeliivadele vett, et suurte kelkude vedamist kergemaks teha. Selline on rahvusvahelise füüsikute töögrupi järeldus, milleni jõuti erinevat tüüpi liivades oleva vee koguse ning hõõrdumise vahelist seost uurides. Uurimusest selgus, et Egiptuse kõrbetes leiduv liivatüüp muutub veega niisutamisel eriti livedaks – fakt, mis võis püramiidide ehitamiseks kasutatud suurte kivimürakate liigutamise […]
Futuristliku õhusõiduki esitlus – pardal on Bayeri materjalid
9. aprill 2014 Payerne, Šveits – visionaarne projekt on nüüdseks avalikustatud: teine päikeseenergial töötav lennuk Solar Impulse on valmis. Lennuk, millega lennatakse 2015. aastal esimest korda kütuseta ümber maailma, avalikustati kolmapäeval Payerne’is Šveitsis. Pardal on arvukalt uuenduslikke tooteid ja lahendusi Bayer MaterialScience’ilt, mis teevad lennuki eriti kergeks ja energiasäästlikuks, nende hulgas ka uus ja äärmiselt […]
Lõppes 2013. – 2014. aasta Eesti õhusaaste mõõtmise kampaania
Äsja lõppes Eesti Füüsika Seltsi ja GLOBE Eesti eestvedamisel 2013. – 2014. aastal toimunud Eesti õhusaaste mõõtmise kampaania. Projektis osales 25 Eesti kooli, mõõdeti tahma ning NO2, O3, NH3 ja SO2 sisaldust õhus. Saadud tulemustega on võimalik tutvuda siin http://www.globe.ee/ohusaaste/?page_id=688. NO2, O3, NH3 ja SO2 mõõtmistulemustest valmis ka gümnaasiumi õpilastele mõeldud andmete analüüs ja suunitlused uurimistöö läbiviimiseks http://www.globe.ee/ohusaaste/?p=704. GLOBE (Global Learning […]
Hübriidne plasma-katalüütiline reaktor ohtlike gaaside eemaldamiseks
Indrek Jõgi, Ants Haljaste, Matti Laan „Hybrid TiO2 based plasma-catalytic reactors for the removal of hazardous gasses“ Surf. Coat. Technol. 242 (2014) 195-199. Kateldes ja mootorites kütuste põlemisel tekkivad lämmastik- ja vääveloksiidid (NOx ja SO2) põhjustavad atmosfääri jõudes happevihmasid ja sudu ning on seetõttu ohuks nii inimeste tervisele kui ka keskkonnale. Seetõttu on nende ühendite […]
Leiti otsene tõend nii kosmilisele inflatsioonile kui gravitatsioonilainetele
Universum tekkis ligikaudu 14 miljardit aastat tagasi nähtusest, mida nimetatakse Suureks Pauguks. Selle alghetkeil paisus kaduvväikse sekundi murdosa jooksul Universum eksponentsiaalselt, kaugele meie parimate teleskoopide vaateulatusest. Ilus lugu, ent kuni selle nädala alguseni katselise tõenduseta. Esmaspäeval teatas Harvard-Smithsonian astrofüüsika keskus oma veebilehel ametlikus teadaandes, et on kosmilisele paisumisele (inflatsioonile) leidnud esimese otsese tõendi. Avastuse au […]
Noored Kooli programmist füüsiku pilguga
Jaak Vaabel lõpetas 2011. aastal Tartu Ülikooli füüsika erialal. Kõigi õpinguist avanenud võimaluste kiuste otsustas ta kandideerida Noored Kooli programmi, osutus väljavalituks ja veetis kaks aastat Lähte Ühisgümnaasiumis füüsikaõpetajana. Praegu töötab ta BigBank’is pangatarkvara haldusspetsialistina. Mida võiks füüsikataustaga noor õpetamisest saada – küsisime Jaagult 4 küsimust. Kuidas tekkis idee Noored Kooli programmi kandideerida? Õpingute ajal […]
Hele täpp varju keskmes
Robert P. Crease võtab vaatluse alla lihtsa demonstratsiooni, mis on ühteaegu nii paeluv hariduslik vahend kui ka draamatiline õppetund ajaloost. ,,See on erakordselt lihtne demonstratsioon,” sõnab Hal Metcalf, lülitades samal ajal sisse väikese laserpointeri, tekitades seega 10m kaugusel asuvale seinale umbes 2mm diameetriga helerohelise täpi. Seejärel klammerdab ta ühe sirge naela hoidja külge ning asetab […]
Kas uus suund fotoonikas?
KBFI teadlased Urmas Nagel ja Toomas Rõõm koostöös Ungari, Jaapani ja Hollandi teadlastega on avastanud uue optilise nähtuse kasutades haruldast eksperimentaalset seadet Tallinnas, kus optiline spektroskoopia on ühildatud tugevate magnetväljadega. Avastus, mis võib olla aluseks uutele suundumustele fotoonikas ja infomatsioonitehnoloogias, on avaldatud ajakirjas Nature Communications. Materjalid, mida rühm uuris Ungari teadlase István Kézsmárki juhtimisel, on […]
TÜ Chemicumis avati Magnetlabor
Tuumamagnetresosnants ehk TMR on teadusele ülikasulik nähtus. Sellega saab mitmekülgselt uurida nii tahke kui vedela aine koostist, jälgida keemiliste reaktsioonide kulgu, uurida rakumembraane ning luua inimese sisemusest ruumilisi pilte. Varem oli Tartus teadlastele kasutada 200 MHz (4,7 T) ning 400 MHz (9,4 T) TMR spektromeetrid. 30.01.14 Chemicumis avatud magnetlaboris seisab aga uus, Brukeri firma 700 […]
Phsyicum
Eesti Füüsikaüliõpilaste Selts saadab tudengid tagasi kooli
Eesti Füüsikaüliõpilaste Selts (FÜS) alustas uut ettevõtmist „Tudeng füüsikatundi“, mille raames saadetakse tudengid gümnaasiumide füüsikatundidesse rääkima füüsikast ning selle etematest väljunditest. Esimesed tunnid anti 13.01.14. ja 15.01.14. Tartus Hugo Treffneri gümnaasiumis. Kokku andsid tudengid kuus tundi, mida said kuulata nii Treffneri humanitaar-, reaal- kui loodusharu õpilased. Füüsikaportaalil õnnestus kohal käia tunnis, mis algas kolmapäeval kell […]
Teaduspõhine otsustamine
Alates kivimite hüdraulilisest purustamisest (ingl. k. fracking) ja tuumenergiast kuni alternatiivmeditsiini ja kliimamuutusteni – miks on teaduslik informatsioon just siis, kui see on eriti oluline, tihtipeale kallutatud või puudub üldsegi? Robert P. Crease proovib leida mõningaid vastuseid.