When a water drop falls on an oscillating soapy water surface it is observed that coalescence of the
drop is inhibited because the drops are bouncing on the surface like on a trampoline. In our
research we made experimental and theoretical investigat…
Transport phenomena and dimensionless numbers: towards a new methodological approach
This review presents a new methodical approach to the classification of dimensionless numbers
as pair relationships of the main forces controlling transport phenomena in fluids at the
macroscopic level by using a tabulated form. To memorize the t…
The International Young Physicists’ Tournament
The International Young Physicists’ Tournament (IYPT), is a competition for teams of secondary
school students, often referred to as the Physics World Cup. This year the 29th IYPT took place in
Russia with a new record of 29 competing teams from ar…
Assessing learning outcomes from experiments in a science competition
The Slovene Science competition for primary school students aged between 6 and 12 years will be
explained briefly. The competition is based on experiments, which should be done well in advance
either at school or at home. An example of the proposed e…
Cape Town collage
Human spaceflight and robotic exploration image of the week: A patchwork of pictures from the International Space Station
Cosmic Bell Test: Measurement Settings from Milky Way Stars
Author(s): Johannes Handsteiner, Andrew S. Friedman, Dominik Rauch, Jason Gallicchio, Bo Liu, Hannes Hosp, Johannes Kofler, David Bricher, Matthias Fink, Calvin Leung, Anthony Mark, Hien T. Nguyen, Isabella Sanders, Fabian Steinlechner, Rupert Ursin, Sören Wengerowsky, Alan H. Guth, David I. Kaiser, Thomas Scheidl, and Anton Zeilinger
Light from two stars in the Milky Way has been used to test an open loophole of quantum physics.
[Phys. Rev. Lett. 118, 060401] Published Tue Feb 07, 2017
Cosmic Bell Test: Measurement Settings from Milky Way Stars
Author(s): Johannes Handsteiner, Andrew S. Friedman, Dominik Rauch, Jason Gallicchio, Bo Liu, Hannes Hosp, Johannes Kofler, David Bricher, Matthias Fink, Calvin Leung, Anthony Mark, Hien T. Nguyen, Isabella Sanders, Fabian Steinlechner, Rupert Ursin, Sören Wengerowsky, Alan H. Guth, David I. Kaiser, Thomas Scheidl, and Anton Zeilinger
Light from two stars in the Milky Way has been used to test an open loophole of quantum physics.
[Phys. Rev. Lett. 118, 060401] Published Tue Feb 07, 2017
Angling up for Mars science
ESA’s latest Mars orbiter has moved itself into a new path on its way to achieving the final orbit for probing the Red Planet.
Fly Your Satellite!
ESA is offering university students a new opportunity to build and test their own CubeSats
Astronomers discover a white dwarf that acts like a pulsar
This star refused to simply go out — instead, the white dwarf it left behind continues to blast its companion with a beam of radiation as a pulsar.
Hubble captures an ailing star’s death knell
The red giant star is in the midst of dispersing into a planetary nebula.
NASA’s Curiosity Rover Sharpens Paradox of Ancient Mars
Evidence shows ancient Mars sometimes had water on its surface. Yet climate modelers struggle to produce scenarios where its surface is warm enough to keep water unfrozen.
Queen Elizabeth Prize Honors Digital Imaging Pioneers
Eric Fossum receives the world’s most prestigious engineering prize for leading a JPL team that developed breakthrough imaging technology in the 1990s.
NASA’s Curiosity Rover Sharpens Paradox of Ancient Mars
Evidence shows ancient Mars sometimes had water on its surface. Yet climate modelers struggle to produce scenarios where its surface is warm enough to keep water unfrozen.
Queen Elizabeth Prize Honors Digital Imaging Pioneers
Eric Fossum receives the world’s most prestigious engineering prize for leading a JPL team that developed breakthrough imaging technology in the 1990s.
A supermassive black hole spent more than a decade consuming a star
Hungry, hungry black hole
A fireball blazed over the midwest last night
The incoming meteor came in with a bang and faded just as quickly.
Shedding star
Space Science Image of the Week: Hubble’s snapshot of a star shedding shells of material
A simple diffraction experiment using banana stem as a natural grating
A simple diffraction experiment was designed using banana stem as natural grating. Coherent beams of
lasers with wavelengths of 632.8 nm and 532 nm that pass through banana stem produce periodic
diffraction patterns on a screen. The diffraction e…
A simple diffraction experiment using banana stem as a natural grating
A simple diffraction experiment was designed using banana stem as natural grating. Coherent beams of
lasers with wavelengths of 632.8 nm and 532 nm that pass through banana stem produce periodic
diffraction patterns on a screen. The diffraction e…
Measurement of the b-Quark Production Cross Section in 7 and 13 TeV pp Collisions
Author(s): R. Aaij et al. (LHCb Collaboration)The cross-section for bottom quark production at 13 TeV, as measured by the LHCb Collaboration, differs from QCD predictions.[Phys. Rev. Lett. 118, 052002] Published Fri Feb 03, 2017
Poynting-Robertson-like Drag at the Sun’s Surface
Author(s): Ian Cunnyngham, Marcelo Emilio, Jeff Kuhn, Isabelle Scholl, and Rock Bush
Detailed solar observations and theory suggest that photons remove angular momentum from the Sun, explaining why the Sun’s surface spins more slowly than its core.
[Phys. Rev. Lett. 118, 051102] Published Fri Feb 03, 2017
Measurement of the b-Quark Production Cross Section in 7 and 13 TeV pp Collisions
Author(s): R. Aaij et al. (LHCb Collaboration)The cross-section for bottom quark production at 13 TeV, as measured by the LHCb Collaboration, differs from QCD predictions.[Phys. Rev. Lett. 118, 052002] Published Fri Feb 03, 2017
Poynting-Robertson-like Drag at the Sun’s Surface
Author(s): Ian Cunnyngham, Marcelo Emilio, Jeff Kuhn, Isabelle Scholl, and Rock Bush
Detailed solar observations and theory suggest that photons remove angular momentum from the Sun, explaining why the Sun’s surface spins more slowly than its core.
[Phys. Rev. Lett. 118, 051102] Published Fri Feb 03, 2017
Week In Images
Our week through the lens: 30 January – 3 February 2017
Yuksek + Thomas Pesquet
A musical video collaboration between Yuksek and ESA astronaut Thomas Pesquet
Tilting a wobbly chair
If a small object is placed under the front leg of a chair, the chair tilts backwards. If the object
is placed under a rear leg, the chair tilts sideways. The effect is surprising but can be analysed
in terms of elementary physics.
Putting more ‘modern’ in modern physics education: a Knowledge Building approach using student questions and ideas about the universe
Student-generated questions and ideas about our universe are the start of a rich and highly
motivating learning environment. Using their curiosity-driven questions and ideas, students form
Knowledge Building groups or ‘communities’ where they pla…
Shadows constructing a relationship between light and color pigments by physical and mathematical perspectives
Full shadows, partial shadows and multilayer shadows are explained based on the phenomenon of the
linear dispersion of light. This paper focuses on progressing the understanding of shadows from
physical and mathematical perspectives. A significant re…
Exorcising Pepper’s ghost
The well-known demonstration of Pepper’s ghost can be enhanced by the use of linear polarisers,
which can make the image disappear.
Understanding the power reflection and transmission coefficients of a plane wave at a planar interface
In most textbooks, after discussing the partial transmission and reflection of a plane wave at a
planar interface, the power (energy) reflection and transmission coefficients are introduced by
calculating the normal-to-interface components of the Poy…
Coefficient of restitution for a superelastic collision
A simple experiment is described where the tip of a metal ruler is used to strike a 50 g mass. Since
the ruler is very flexible, the impact duration is much longer than usual, giving the impression
that the ruler simply pushes the mass forward at lo…
Insights from simple models for surface states in nanostructures
Surface passivation is of great technological importance due to the increasing miniaturisation of
electronic devices. It has been known for many years that under certain conditions surface states
can form; when they do so in a quantum well (QW) the r…
Measurement of the ratio h / e with a photomultiplier tube and a set of LEDs
We propose a laboratory experience aimed at undergraduate physics students to understand the main
features of the photoelectric effect and to perform a measurement of the ratio h / e , where h is
Planck’s constant and e is the electron charge. The …
Teaching advanced science concepts through Freshman Research Immersion
We have developed a new introductory physics/chemistry programme that teaches advanced science
topics and practical laboratory skills to freshmen undergraduate students through the use of
student-led, bona fide research activities. While many recent …
Quantum harmonic oscillator: an elementary derivation of the energy spectrum
An elementary treatment of the quantum harmonic oscillator is proposed. No previous knowledge of
linear differential equation theory or Fourier analysis are required, but rather only a few basics
of elementary calculus. The pivotal role in our analys…
Teaching advanced science concepts through Freshman Research Immersion
We have developed a new introductory physics/chemistry programme that teaches advanced science
topics and practical laboratory skills to freshmen undergraduate students through the use of
student-led, bona fide research activities. While many recent …
Insights from simple models for surface states in nanostructures
Surface passivation is of great technological importance due to the increasing miniaturisation of
electronic devices. It has been known for many years that under certain conditions surface states
can form; when they do so in a quantum well (QW) the r…
Understanding the power reflection and transmission coefficients of a plane wave at a planar interface
In most textbooks, after discussing the partial transmission and reflection of a plane wave at a
planar interface, the power (energy) reflection and transmission coefficients are introduced by
calculating the normal-to-interface components of the Poy…
Quantum harmonic oscillator: an elementary derivation of the energy spectrum
An elementary treatment of the quantum harmonic oscillator is proposed. No previous knowledge of
linear differential equation theory or Fourier analysis are required, but rather only a few basics
of elementary calculus. The pivotal role in our analys…
Measurement of the ratio h / e with a photomultiplier tube and a set of LEDs
We propose a laboratory experience aimed at undergraduate physics students to understand the main
features of the photoelectric effect and to perform a measurement of the ratio h / e , where h is
Planck’s constant and e is the electron charge. The …
Coefficient of restitution for a superelastic collision
A simple experiment is described where the tip of a metal ruler is used to strike a 50 g mass. Since
the ruler is very flexible, the impact duration is much longer than usual, giving the impression
that the ruler simply pushes the mass forward at lo…
Exorcising Pepper’s ghost
The well-known demonstration of Pepper’s ghost can be enhanced by the use of linear polarisers,
which can make the image disappear.
Putting more ‘modern’ in modern physics education: a Knowledge Building approach using student questions and ideas about the universe
Student-generated questions and ideas about our universe are the start of a rich and highly
motivating learning environment. Using their curiosity-driven questions and ideas, students form
Knowledge Building groups or ‘communities’ where they pla…
Shadows constructing a relationship between light and color pigments by physical and mathematical perspectives
Full shadows, partial shadows and multilayer shadows are explained based on the phenomenon of the
linear dispersion of light. This paper focuses on progressing the understanding of shadows from
physical and mathematical perspectives. A significant re…
Tilting a wobbly chair
If a small object is placed under the front leg of a chair, the chair tilts backwards. If the object
is placed under a rear leg, the chair tilts sideways. The effect is surprising but can be analysed
in terms of elementary physics.
PT-Symmetric Real Dirac Fermions and Semimetals
Author(s): Y. X. Zhao and Y. Lu
Real monopole charges–generalizations of complex Weyl monopoles–are identified theoretically to have combined inversion and time-reversal symmetry. These charges could be realized in cold atom systems.
[Phys. Rev. Lett. 118, 056401] Published Thu Feb 02, 2017
Two-Element Mixture of Bose and Fermi Superfluids
Author(s): Richard Roy, Alaina Green, Ryan Bowler, and Subhadeep GuptaA bosonic-fermionic superfluid mixture containing two different atomic species is reported for the first time. This system could be used to probe collective properties and the genera…
Direct Observation of Spatiotemporal Dynamics of Short Electron Bunches in Storage Rings
Author(s): C. Evain, E. Roussel, M. Le Parquier, C. Szwaj, M.-A. Tordeux, J.-B. Brubach, L. Manceron, P. Roy, and S. BielawskiThe shape of various Terahertz radiation pulses used in synchrotrons is measured with picosecond resolution.[Phys. Rev. Lett. …
Quantum Performance of Thermal Machines over Many Cycles
Author(s): Gentaro Watanabe, B. Prasanna Venkatesh, Peter Talkner, and Adolfo del Campo
Theoretical calculations show that the performance of a quantum heat engine over several cycles can’t be judged by analyzing just a single cycle.
[Phys. Rev. Lett. 118, 050601] Published Thu Feb 02, 2017
PT-Symmetric Real Dirac Fermions and Semimetals
Author(s): Y. X. Zhao and Y. Lu
Real monopole charges–generalizations of complex Weyl monopoles–are identified theoretically to have combined inversion and time-reversal symmetry. These charges could be realized in cold atom systems.
[Phys. Rev. Lett. 118, 056401] Published Thu Feb 02, 2017
Two-Element Mixture of Bose and Fermi Superfluids
Author(s): Richard Roy, Alaina Green, Ryan Bowler, and Subhadeep GuptaA bosonic-fermionic superfluid mixture containing two different atomic species is reported for the first time. This system could be used to probe collective properties and the genera…
Direct Observation of Spatiotemporal Dynamics of Short Electron Bunches in Storage Rings
Author(s): C. Evain, E. Roussel, M. Le Parquier, C. Szwaj, M.-A. Tordeux, J.-B. Brubach, L. Manceron, P. Roy, and S. BielawskiThe shape of various Terahertz radiation pulses used in synchrotrons is measured with picosecond resolution.[Phys. Rev. Lett. …
Quantum Performance of Thermal Machines over Many Cycles
Author(s): Gentaro Watanabe, B. Prasanna Venkatesh, Peter Talkner, and Adolfo del Campo
Theoretical calculations show that the performance of a quantum heat engine over several cycles can’t be judged by analyzing just a single cycle.
[Phys. Rev. Lett. 118, 050601] Published Thu Feb 02, 2017
Earth from Space
Join us Friday, 3 February, at 10:00 CET for the ‘Earth from Space’ video programme. This week features wetlands in Iran, at the northern tip of the Persian Gulf
The case of Ceres’ disappearing volcanoes
Is Ceres’ lone cryovolcano truly alone, or have its peers simply flattened out over time?
How Groundhogs Day and astronomy intersect
How much wood would a woodchuck chuck?
A new recruit for ESA’s astronaut corps
Matthias Maurer, from Germany, has started his astronaut training as part of ESA’s astronaut corps.
Botswana wetlands
Marking World Wetlands Day, this Sentinel-2A image features the Okavango Delta in Botswana – a lifeline for local communities and wildlife alike
Swirling spirals at the north pole of Mars
A new mosaic from ESA’s Mars Express shows off the Red Planet’s north polar ice cap and its distinctive dark spiralling troughs.
Visual explanations behind important equations in astronomy
When connections between related observations and facts are not being made, introductory science
classes can be perceived as an accumulation of disjointed equations with the risk of losing both
students’ interest as well as their grasp of the mater…
Visual explanations behind important equations in astronomy
When connections between related observations and facts are not being made, introductory science
classes can be perceived as an accumulation of disjointed equations with the risk of losing both
students’ interest as well as their grasp of the mater…
It’s Never ‘Groundhog Day’ at Jupiter
NASA Juno to Fly By Gas Giant Thursday.
It’s Never ‘Groundhog Day’ at Jupiter
NASA Juno to Fly By Gas Giant Thursday.
It’s Never ‘Groundhog Day’ at Jupiter
NASA Juno to Fly By Gas Giant Thursday.
Superdense Coding over Optical Fiber Links with Complete Bell-State Measurements
Author(s): Brian P. Williams, Ronald J. Sadlier, and Travis S. HumbleResearchers have demonstrated the fiber transmission of quantum information in which each quantum bit carries nearly two bits of classical information.[Phys. Rev. Lett. 118, 050501] P…
Superdense Coding over Optical Fiber Links with Complete Bell-State Measurements
Author(s): Brian P. Williams, Ronald J. Sadlier, and Travis S. HumbleResearchers have demonstrated the fiber transmission of quantum information in which each quantum bit carries nearly two bits of classical information.[Phys. Rev. Lett. 118, 050501] P…
A newly discovered asteroid is zipping between Earth and the Moon tomorrow
We’ll have a close encounter almost as soon as we’ve discovered it.
How Harvard’s vast collection of glass plates still shapes astronomy
A group of dedicated women made astounding discoveries in the late 19th and early 20th century. Those plates still resonate as one of the greatest astronomical archives known.
ESO’s newest nebula image may be the biggest picture it’s ever taken
At 49,511 x 39,136 pixels, the image clocks in at 5.4 GB.
Steering for the Sun
Technology image of the week: testing a mechanism that will align the solar wings of Europe’s latest weather satellite
NuSTAR Helps Solve ‘Rapid Burster’ Mystery
Scientists observing a neutron star in the “Rapid Burster” system may have solved a 40-year-old mystery surrounding its puzzling X-ray bursts.
NuSTAR Helps Solve ‘Rapid Burster’ Mystery
Scientists observing a neutron star in the “Rapid Burster” system may have solved a 40-year-old mystery surrounding its puzzling X-ray bursts.
Thomas feels home
Human spaceflight and robotic explorations image of the week: ESA astronaut Thomas Pesquet feeling objects in the Netherlands from space
Direct Identification of Dilute Surface Spins on Al_{2} O_{3} : Origin of Flux Noise in Quantum Circuits
Author(s): S. E. de Graaf, A. A. Adamyan, T. Lindström, D. Erts, S. E. Kubatkin, A. Ya. Tzalenchuk, and A. V. Danilov
Electron-spin-resonance experiments identify surface electron spin noise as the source of flux noise in superconducting qubit circuits.
[Phys. Rev. Lett. 118, 057703] Published Tue Jan 31, 2017
Observation of Classical-Quantum Crossover of 1/f Flux Noise and Its Paramagnetic Temperature Dependence
Author(s): C. M. Quintana et al.
Measurements of the classical and quantum components of the flux noise in a superconducting qubit indicate that the noise has a paramagnetic origin.
[Phys. Rev. Lett. 118, 057702] Published Tue Jan 31, 2017
Realization of Translational Symmetry in Trapped Cold Ion Rings
Author(s): Hao-Kun Li, Erik Urban, Crystal Noel, Alexander Chuang, Yang Xia, Anthony Ransford, Boerge Hemmerling, Yuan Wang, Tongcang Li, Hartmut Häffner, and Xiang Zhang
40Ca+ ions in a ring are stabilized to a degree that individual particles can be accessed and controlled.
[Phys. Rev. Lett. 118, 053001] Published Tue Jan 31, 2017
Direct Identification of Dilute Surface Spins on Al_{2} O_{3} : Origin of Flux Noise in Quantum Circuits
Author(s): S. E. de Graaf, A. A. Adamyan, T. Lindström, D. Erts, S. E. Kubatkin, A. Ya. Tzalenchuk, and A. V. Danilov
Electron-spin-resonance experiments identify surface electron spin noise as the source of flux noise in superconducting qubit circuits.
[Phys. Rev. Lett. 118, 057703] Published Tue Jan 31, 2017
Observation of Classical-Quantum Crossover of 1/f Flux Noise and Its Paramagnetic Temperature Dependence
Author(s): C. M. Quintana et al.
Measurements of the classical and quantum components of the flux noise in a superconducting qubit indicate that the noise has a paramagnetic origin.
[Phys. Rev. Lett. 118, 057702] Published Tue Jan 31, 2017
Realization of Translational Symmetry in Trapped Cold Ion Rings
Author(s): Hao-Kun Li, Erik Urban, Crystal Noel, Alexander Chuang, Yang Xia, Anthony Ransford, Boerge Hemmerling, Yuan Wang, Tongcang Li, Hartmut Häffner, and Xiang Zhang
40Ca+ ions in a ring are stabilized to a degree that individual particles can be accessed and controlled.
[Phys. Rev. Lett. 118, 053001] Published Tue Jan 31, 2017
New interactive chart shows just how many satellites are orbiting Earth
Just how much future space trash is up there?
New Planet Imager Delivers First Science
A new device on the W.M. Keck Observatory in Hawaii has delivered its first images, showing a ring of planet-forming dust around a star.
Troy High School Places First at Regional Science Bowl
It was the 25th year JPL has hosted the event.
Troy High School Places First at Regional Science Bowl
It was the 25th year JPL has hosted the event.
New Planet Imager Delivers First Science
A new device on the W.M. Keck Observatory in Hawaii has delivered its first images, showing a ring of planet-forming dust around a star, and separately, a cool, star-like body, called a brown dwarf, lying near its companion star.
Close Views Show Saturn’s Rings in Unprecedented Detail
Newly released images showcase the incredible closeness with which NASA’s Cassini spacecraft, now in its “Ring-Grazing” orbits phase, is observing Saturn’s dazzling rings of icy debris.
Close Views Show Saturn’s Rings in Unprecedented Detail
Newly released images showcase the incredible closeness with which NASA’s Cassini spacecraft, now in its “Ring-Grazing” orbits phase, is observing Saturn’s dazzling rings of icy debris.
Sympathetic Ground State Cooling and Time-Dilation Shifts in an ^{27} Al^{+} Optical Clock
Author(s): J.-S. Chen, S. M. Brewer, C. W. Chou, D. J. Wineland, D. R. Leibrandt, and D. B. Hume
A novel method for cooling trapped ions could boost the accuracy of atomic clocks.
[Phys. Rev. Lett. 118, 053002] Published Mon Jan 30, 2017
Sympathetic Ground State Cooling and Time-Dilation Shifts in an ^{27} Al^{+} Optical Clock
Author(s): J.-S. Chen, S. M. Brewer, C. W. Chou, D. J. Wineland, D. R. Leibrandt, and D. B. Hume
A novel method for cooling trapped ions could boost the accuracy of atomic clocks.
[Phys. Rev. Lett. 118, 053002] Published Mon Jan 30, 2017
Wind satellite heads for final testing
The road to realising ESA’s Aeolus mission may have been long and bumpy, but developing novel space technology is, by its very nature, challenging. With the satellite now equipped with its revolutionary instrument, the path ahead is much smoother as it heads to France to begin the last round of tests before being shipped to the launch site at the end of the year.
‘Earth wind’ bathes the Moon with oxygen
To study the ancient history of the Earth, we should look to the moon.
A new study from Japanese researchers reveals that for the past 2.4 billion years, the moon has been bathed in a stream of oxygen particles stripped from the Earth’s atmosphe…
Cassini’s final days begin with the most detailed images of Saturn’s rings to date
As Cassini prepares to enter its Grand Finale, it’s still wowing astronomers with high-resolutions images of ring structures like nothing we’ve ever seen before.
Up close and personal
The Soyuz carrying ESA’s new SmallGEO telecom platform is captured at the moment of liftoff on a rainy evening in Kourou
Solar cell test
Space Science Image of the Week: Testing the solar cells of ESA’s exoplanet mission
SmallGEO liftoff
Watch the replay of the first launch of ESA’s SmallGEO platform at 01:03 GMT on 28 January from Europe’s Spaceport in French Guiana
Storms Filled 37 Percent of CA Snow-Water Deficit
January storms may have recouped 37 percent of California’s five-year deficit in snow water.
Storms Filled 37 Percent of CA Snow-Water Deficit
January storms may have recouped 37 percent of California’s five-year deficit in snow water.
Vulnerability and Cosusceptibility Determine the Size of Network Cascades
Author(s): Yang Yang, Takashi Nishikawa, and Adilson E. MotterSpecific clusters within a network tend to fail consistently as part of large-scale network failures, such as those in electrical grids or airline transportation systems.[Phys. Rev. Lett. 11…
One-Dimensional Self-Organization and Nonequilibrium Phase Transition in a Hamiltonian System
Author(s): Jiao Wang and Giulio CasatiNonequilibrium phase transitions, known from 2D and 3D systems, are also demonstrated in 1D, with implications for transport in these systems.[Phys. Rev. Lett. 118, 040601] Published Fri Jan 27, 2017
Topologically Entangled Rashba-Split Shockley States on the Surface of Grey Arsenic
Author(s): Peng Zhang, J.-Z. Ma, Y. Ishida, L.-X. Zhao, Q.-N. Xu, B.-Q. Lv, K. Yaji, G.-F. Chen, H.-M. Weng, X. Dai, Z. Fang, X.-Q. Chen, L. Fu, T. Qian, H. Ding, and S. ShinElectronic states that only exist on the surface and not in the bulk are predi…