Seeing the wood for the trees: could forests be used as neutrino detectors?

21 Feb 2024

Treemendous: trees could detect radio waves at frequencies of interest for tau neutrinos (courtesy: Shutterstock/Conny-Sjostrom)

Trees could shed light on some of the most cataclysmic events in the universe, according to a particle physicist at the University of Kansas in the US. Steven Prohira thinks these woody objects could function as radio antennas to spot neutrinos, with forests forming large detector arrays. Prohira argues that such detectors could be cheaper and easier to deploy than arrays of artificial antennas (arXiv: 2401.14454).

 

Graphene-based materials show great promise for hydrogen transport and storage

08 Feb 2024 Hamish Johnston

Hydrogen can be used as a carbon-free source of energy in a wide range of applications including home heating, transportation and industry. However, there are significant challenges that must be overcome to ensure the safe and efficient storage and transportation of the gas.

In this episode of the Physics World Weekly podcast, the materials expert Krzysztof Koziol explains why he is developing graphene-based materials and polymers to facilitate a hydrogen economy.

 

Bionic jellyfish and more efficient windfarms: a conversation with John Dabiri

15 Feb 2024 Hamish Johnston

Jellyfish have a very simple, yet very effective way of swimming – and this has attracted the attention of the aeronautics engineer John Dabiri at the California Institute of Technology. In this episode of the Physics World Weekly podcast, Dabiri talks about his work on the artificial enhancement of jellyfish. He also explains how fluid dynamics can be used to boost the efficiency of windfarms, and explores the possibility that swimming organisms play important role in the mixing of the oceans.

 

Tackling climate change while improving human wellbeing

07 Mar 2024 Hamish Johnston

Environmental challenges like climate change are forcing us to rethink how we live in cities. This provides humanity with an important opportunity to develop new policies that also improve the overall wellbeing of urban dwellers.

Our guest in this episode of Physics World Weekly podcast is Radhika Khosla – who is an urban climatologist based at the Oxford Smith School of Enterprise and the Environment at the UK’s University of Oxford.

 

Researchers reveal the fluid dynamics behind cicadas’ ‘unique’ urination

16 Mar 2024 Michael Banks

This year promises to be a bumper one for cicadas, given that 2024 marks the first time in more than 200 years that two broods belonging to two species will emerge simultaneously.

Now, researchers at Georgia Institute of Technology in the US say we might have more to worry about than just the cacophony the insects are famous for.

 

When it comes to fish dynamics, there's a school

28 Mar 2024 Michael Banks

Researchers find that three fish is the minimum number to form a school. (Courtesy: University of Bristol/Yushi Yang))

How many fish make up a school? It sounds like one of those trick questions, but physicists at Heinrich Heine University Düsseldorf and the University of Bristol have now found an answer.

To do so they fitted a “bowl-shaped” aquarium at Bristol University with cameras to track the three-dimensional trajectories of zebrafish, studying group sizes of two, three, four and fifty fish (Nature Comms 15 2591).

 

Why error correction is quantum computing’s defining challenge

25 Mar 2024

Steve Brierley argues that quantum computers must implement comprehensive error-correction techniques before they can become fully useful to society

Exploiting their advantage Quantum computers will only become useful once hardware and software tools can control inherently unstable qubits. (Courtesy: Riverlane)“There are no persuasive arguments indicating that commercially viable applications will be found

 

Scientists discovered that like-charged particles can sometimes attract

22 Mar 2024

“Electrosolvation force” Negatively charged silica microparticles suspended in water attract each other to form hexagonal clusters. (Courtesy: Zhang Kang)

From a young age, we are taught in school that like charges – whether both positive or both negative – will repel each other, while opposite charges attract. It turns out that under certain conditions, like charges can actually attract each other instead. In work recently published in Nature Nanotechnology, researchers at the University of Oxford have demonstrated the attraction of like-charged particles in solutions.

Superfluid helium: the quantum curiosity behind huge experiments like the LHC

 

Superfluid helium: the quantum curiosity behind massive experiments like the LHC

28 Mar 2024 Hamish Johnston

The effects of quantum mechanics are all around us, but the quantum properties of matter are generally only apparent at the microscopic level. Superfluidity is an exception, and some of its bizarre characteristics can be seen with the naked eye. Moreover, superfluid helium II has found several critical applications in science and technology – and is used in multi-tonne quantities today at facilities like the Large Hadron Collider.

ELECTROMAGNETIC INDUCTION

Electromagnetic induction is a fundamental concept in physics that describes generating an electromotive force (EMF) in a conductor when exposed to a changing magnetic field. Michael Faraday first discovered this phenomenon in the early 19th century, and it has since become a cornerstone of modern technology, playing a crucial role in developing electric generators, transformers, and various other electrical devices.

At its core, electromagnetic induction is based on the principle of magnetic flux. Magnetic flux measures the total magnetic field passing through a given area and is directly proportional to the strength of the magnetic field and the area it passes through. When a conductor is placed in a changing magnetic field, the magnetic flux through the conductor also changes, which induces an EMF in the conductor according to Faraday's law of electromagnetic induction.

APPLICATIONS OF THE MOTION OF CHARGED PARTICLES

INTRODUCTION

Physics is a vast field that includes the study of matter, energy, and their interactions. One of the most fascinating aspects of physics is the motion of charged particles, which plays a key role in a wide range of applications, from electronics to medical imaging.

Charged particles, such as electrons and protons, are fundamental building blocks of matter. When these particles are in motion, they create electric and magnetic fields that can be harnessed for various purposes. One of the best-known applications of charged particle motion is in electronics. In electronic devices such as computers and smartphones, charged particles flow through circuits, carrying information and powering the device. Electric and magnetic fields control the movement of these particles, allowing precise manipulation of electrical signals.

 

New ion-trapping approach could help quantum computers scale up

25 Mar 2024

Ions on the move: To create this image, the ETH Zürich researchers repeatedly transported a single trapped ion from its initial position (red circle) to 58 other positions, imaged it in its new location, and returned it to its starting point. They repeated this sequence 172 times. (Courtesy: Jain, S, Sägesser, T, Hrmo, P et al., Penning micro-trap for quantum computing. Nature 627, 510–514 (2024). https://doi.org/10.1038/s41586-024-07111-x)

Trapping ions with static magnetic and electric fields instead of an oscillating electromagnetic field could make it easier to use ions as building blocks for quantum computers. The new approach, which was developed by researchers at ETH Zurich in Switzerland, allows better control of an ion’s quantum state and position, and marks an important step towards scaling up trapped ions as a platform for quantum computation.

 

Controllable Cooper pair splitter could separate entangled electrons on demand

14 Mar 2024 Isabelle Dumé

Qubit material: A figure that schematically shows how split Cooper pairs might be fed into a quantum computer that operates with entangled electrons. (Courtesy: Fredrik Brange)

Entangled particles – that is, those with quantum states that remain correlated regardless of the distance between them – are important for many quantum technologies. Devices called Cooper-pair splitters can, in principle, generate such entangled particles by separating the electrons that pair up within superconducting materials, but the process was considered too random and uncontrollable to be of practical use.

Physicists at Aalto University in Finland have now put forward a theoretical proposal indicating that these electron pairs could, in fact, be split on demand by applying time-dependent voltages to quantum dots placed on either side of a superconducting strip. The technique, which preserves the entangled state of the separated electrons, might aid the development of quantum computers that use entangled electrons as quantum bits (qubits).

 

The ultraviolet dual-comb spectroscopy system counts single photons

13 Mar 2024

How it works: the top frequency comb is passed through a sample of interest and then into a beamsplitter. The bottom frequency comb operates at a slightly different pulse repetition frequency and is combined with the top comb in the beamsplitter. Photons in the combined beam are counted by a detector. (Courtesy: Bingxin Xu et al/Nature/ CC BY 4.0 DEED)

Dual-comb spectroscopy – absorption spectroscopy that utilizes the interference between two frequency combs – has been performed at ultraviolet wavelengths using single photons. The work could lead to the use of the technique at shorter wavelengths, where high-power comb lasers are unavailable. The technique could also find new applications.

 

New metamaterial could make true one-way glass

18 Mar 2024 Isabelle Dumé

The magnetic properties of a material can affect how it interacts with light. (Courtesy: Ihar Faniayeu/University of Gothenburg)

A proposed new optical metamaterial could behave like true one-way glass thanks to the Tellegen effect, which connects a material’s response to light waves with its magnetization and polarization. Under the design put forward by researchers in Finland, the US, Sweden and Greece, the new metamaterial would be formed from randomly oriented nanocylinders consisting of ferromagnets and a high-permittivity dielectric that operates at the right resonance. Unlike previous proposals, the metamaterial would not require external magnetic fields to operate, and its developers say it could also make solar cells more efficient.

 

Physicists take the temperature of the second sound

13 Feb 2024

Wave as you go by: The term "second sound" refers to the movement of heat through a superfluid. (Courtesy: Jose-Luis Olivares, MIT)

A new technique for monitoring “second sound” – a bizarre type of heat wave that occurs in superfluids – has been developed by physicists in the US. The work could help model a variety of scientifically interesting and poorly understood systems, including high temperature superconductors and neutron stars.

The term “second sound” was coined by the Soviet physicist Lev Landau in the 1940s after his colleague László Tisza suggested that the bizarre properties of liquid helium might be explained by considering it as a mixture of two fluids: a normal fluid and a superfluid that flowed without friction. This arrangement gives rise to the possibility that, if the superfluid and normal fluid flow in opposite directions, the material will not experience any apparent disturbance, but heat will nevertheless pass through it like a wave as the normal fluid and superfluid switch places.

 

Physics World reveals its top 10 Breakthroughs of the Year for 2023

07 Dec 2023 Hamish Johnston

Physics World is delighted to announce its top 10 Breakthroughs of the Year for 2023, which ranges from research in astronomy and medical physics to quantum science, atomic physics and more. The overall Physics World Breakthrough of the Year will be revealed on Thursday 14 December.

The 10 Breakthroughs were selected by a panel of Physics World editors, who sifted through hundreds of research updates published on the website this year across all fields of physics. In addition to having been reported in Physics World in 2023, selections must meet the following criteria:Significant advance in knowledge or understanding

Importance of work for scientific progress and/or development of real-world applications

Of general interest to Physics World readers

 

Soap bubbles transform into lasers

15 Mar 2024 Stefan Popa

Glowing bubbles: A soap bubble lasing on the end of a capillary tube. (Courtesy: Matjaž Humar and Zala Korenjak/Jožef Stefan Institute)

Soap has long been a household staple, but scientists in Slovenia have now found a new use for it by transforming soap bubbles into tiny lasers. Working at the Jožef Stefan Institute and the University of Ljubljana, they began by creating soap bubbles a few millimetres in diameter. When they mixed these with a fluorescent dye and pumped them with a pulsed laser, the bubbles began to lase. The wavelengths of light the bubble emits are highly responsive to its size, paving the way for bubble-laser sensors that can detect tiny changes in pressure or ambient electric field.

 

Mapping brain circuits reveals potential treatment targets for brain disorders

15 Mar 2024 Tami Freeman

Disease-specific streamlines Deep brain stimulation revealed the fibre bundles associated with symptom improvement in Parkinson’s disease (green), dystonia (yellow), Tourette’s syndrome (blue) and obsessive-compulsive disorder (red). (Courtesy: Barbara Hollunder)

The brain’s frontal circuits play a vital role in controlling motor, cognitive and behavioural functions. Disruption of the fronto-subcortical circuits, which connect the frontal cortex in the forebrain with basal ganglia located deeper within, can result in a range of neurological disorders. It’s not clear, however, which connections are associated with which dysfunctions. To shed light on this problem and help identify potential treatment targets, an international research team has used deep brain stimulation (DBS) to map the circuits associated with four different brain disorders.

 

Functional ultrasound imaging provides real-time feedback during spinal surgery

25 Mar 2024 Tami Freeman

Optimizing pain relief Vasileios Christopoulos, assistant professor of bioengineering at UC Riverside, helped develop functional ultrasound imaging technology to image spinal cord activity. The technique will enable clinicians performing electrical stimulation treatment for back pain to see the effectiveness of the treatments in real time. (Courtesy: Stan Lim/UCR)

Damage to the spinal cord, whether by injury or disease, can have devastating impacts on health, including loss of motor or sensory functions, or chronic back pain, which affects an estimated 540 million people at any given time. A US-based research team has now used functional ultrasound imaging (fUSI) to visualize the spinal cord and map its response to electrical stimulation in real time, an approach that could improve treatments of chronic back pain.

 

Why you shouldn’t be worried about talk of a ‘quantum winter’

26 Mar 2024 James McKenzie

A recent fall in global private investment in quantum technology has led to suggestions that the sector is heading for a downturn. James McKenzie is unfazed and believes the future for the sector is bright.

Cashing in There's money to be made from quantum 2.0 technology. (Courtesy: iStock/monsitj)

For politicians, funders and investors, science isn’t always on their radar. But from time to time, certain fields do capture wider attention. We saw that in the 1950s with nuclear power, which some thought would one day be “too cheap to meter”. Later, nanotechnology and graphene rose to the fore. More recently, artificial intelligence and quantum technology seem to be on everyone’s mind.

 

European Space Agency gives construction go-ahead for LISA gravitational-wave mission

01 Feb 2024 Michael Banks

Ripples in space: LISA will consist of three identical satellites placed in an equilateral triangle in space, with each side of the triangle being 2.5 million kilometres – more than six times the distance between the Earth and the Moon (courtesy: EADS Astrium).

The European Space Agency (ESA) has formally approved the start of construction for its space-based gravitational-wave mission. Work on the Laser Interferometer Space Antenna (LISA) will begin in January 2025 once an industry partner has been chosen to build the craft. LISA, which is estimated to cost €1.5bn, is expected to launch in 2035 and operate for at least four years.

Gravitational waves are distortions of space–time that occur when massive bodies, such as black holes, are accelerated. They were first detected in 2016 by researchers working on the Advanced Laser Interferometer Gravitational-wave Observatory (aLIGO) located in Hanford, Washington and Livingston, Louisiana.

ELECTRIC CURRENT IN BIOLOGY, BIOCHEMISTRY, AND BIOPHYSICS

The electric current in biology, biochemistry, and biophysics plays a critical role in the functioning of living organisms.

The movement of electrical current is essential for various biological processes, from cellular communication to the generation of muscle contraction.

In this article, we will explore the importance of electricity in these industries and how it affects the behavior and functions of living systems.

 The significance of bioelectricity function in robotic microsurgery technology and the procedural steps of implanting microchips in the human brain for functional body movement and thought-generating human movement commands

 In recent years, there have been significant advancements in robotic microsurgery technology, particularly in bioelectricity functionality.

Bioelectricity refers to the electrical signals generated within living organisms, including humans. These signals control physiological functions such as muscle movement, sensory perception, and cognitive processes.

 Integrating bioelectricity into robotic microsurgery technology has opened up new possibilities for improving surgical procedures' precision, efficiency, and effectiveness.

 One of the critical areas where bioelectricity functionality is essential in robotic microsurgery technology is the development of brain-computer interfaces (BCIs). BCIs enable direct communication between the human brain and external devices, such as robotic limbs or computer systems. By harnessing the electrical signals generated by the brain, BCIs can allow individuals with physical disabilities to control prosthetic limbs or interact with digital interfaces using only their thoughts.

 

Carbon nanotubes make optical sensor flexible and ultrathin

22 Feb 2024

Carbon nanotube: these structures have been used to create a new and flexible light sensor. (Courtesy: iStock/theasis)

A flexible, ultrathin optical sensor that uses carbon nanotubes to convert light into electrical signals has been unveiled by Rei Kawabata and colleagues. The team at Japan’s Osaka University says that the device could lead to better optical imaging technologies.

Optical sensors play a vital role in modern imaging technologies. So far, conventional sensors have broadly relied on conventional semiconducting elements to convert light into electrical signals. To avoid damage, however, these devices tend to be mounted on thick, sturdy boards, limiting the shapes of the surfaces they are able to image close up.

 

Can flexoelectricity explain the charging by friction conundrum?

20 Sep 2019 Anna Demming

Charging from friction. Flexoelectricity and tribology may explain how. Credit: Laurence Marks/Northwestern University

The electric shock you get from shuffling along a carpet might be the first experiment in electrostatics and tribology in most people’s lives, but what causes it remains an open question. “A lot of people had worked on what was taking place, for instance that electrons or ions were getting transferred from one material to another,” says Laurence Marks, a professor at Northwestern University in the US. “However, why this should occur in the first place was not understood.”

 

Drinking bird toy generates usable electricity

24 Mar 2024 Hamish Johnston

Dippy device: the team’s generator could power 20 LCDs. (Courtesy: Device/Wu Zheng Qin et al.)

Before we had Instagram and TikTok to amuse us, we had an array of quirky desktop toys that captivated our imaginations. Some of these even demonstrated physical principles – including Newton’s cradle with its suspended spheres that clacked back and forth.

For me, the most mysterious of these toys is the drinking bird. Often called a dippy bird, it pivots about an axle, continuously dipping its beak in and out of a container of liquid with no obvious source of power.

 

Physicists observe false vacuum decay in a ferromagnetic superfluid

12 Feb 2024 Isabelle Dumé

Bubbling away: In the quantum gases lab in Trento, the team produced a superfluid spin mixture of sodium atoms in a false vacuum state (blue) and observed and studied its decay to the true vacuum state (red) through the formation of spin bubbles. (Courtesy: G Lamporesi, A Recati and A Zenesini)

Physicists in Italy have observed a phenomenon known as false vacuum decay for the first time. The work, which was performed in a ferromagnetic superfluid, advances our understanding of ferromagnetic phase transitions and could shed more light on the stability of the early universe.

 

Radiology societies call for critical evaluation of AI, building the UK’s quantum workforce

29 Feb 2024 Hamish Johnston

Artificial intelligence (AI) shows great promise for use in radiology, which involves the use of medical imaging to diagnose and treat disease. Integrating AI tools into radiology could advance the diagnosis, quantification and management of multiple medical conditions. However, it is essential to acknowledge that some AI products may be add little value or even have potential to cause harm.

 

Modelling lung cells could help personalize radiotherapy

12 Mar 2024

Simulating an alveolar segment Computational model of alveolar tissue consisting of 18 alveoli, the tiny air sacs within the lungs. (Courtesy: ©University of Surrey/GSI).

A new type of computer model that can reveal radiation damage at the cellular level could improve radiotherapy outcomes for lung cancer patients.

Roman Bauer, a computational neuroscientist at the University of Surrey in the UK, in collaboration with Marco Durante and Nicolò Cogno from GSI Helmholtzzentrum für Schwerionenforschung in Germany, created the model, which simulates how radiation interacts with the lungs on a cell-by-cell basis.

 

Compton camera measures gamma-ray polarization in nuclear physics experiment

20 Mar 2024

Nuclear structure: the inner workings of some rare nuclei could soon be better understood by using a multilayer Compton camera. (Courtesy: iStock/Girolamo-Sferrazza-Papa)

A Compton camera has been used to measure the polarization of gamma rays in a nuclear physics experiment. This was done by a team led by Shintaro Go at Japans’s RIKEN Cluster for Pioneering Research. They say that that their novel approach could help physicists to probe the structure of atomic nuclei in much better detail.

An atomic nuclei contains protons and neutrons that are bound together by the strong force. Much like electrons in an atom or molecule, these protons and neutrons can exist in a number of distinct energy states – often associated with different shapes of the nucleus. Transitions between these states often involve the emission of gamma-ray photons and the study of these photons provides important information about the internal structure of nuclei – a discipline called nuclear spectroscopy.

 

Diamond alignment makes high-pressure magnetometry of superconductors possible

28 Feb 2024

Cool under pressure: Norman Yao adjusts a diamond anvil cell containing nitrogen–vacancy centres. The instrument sits on top of a positioning system inside a cryostat. (Courtesy: Paul Horowitz/Harvard University)

Physicists in the US and China have devised a technique for making reliable measurements of the magnetic properties of materials held under very high pressures. Their method could help researchers discover materials that are superconductors at high temperatures and high pressures.

High-temperature superconductivity has hit the headlines regularly in the past year or two – but often for the wrong reasons. Several claims of materials that superconduct at close to or even above room temperature have been disputed, and some have been withdrawn.

 

US Odysseus mission becomes first private craft to successfully land on the Moon

23 Feb 2024

Lunar bound: Odysseus from the US firm Intuitive Machines has become the first US mission to make a soft landing on the Moon since Apollo 17 in December 1972 (courtesy: Intuitive Machines)

A private US firm has successfully made a soft landing on the Moon. The Odysseus mission touched down at 6:24 p.m. ET on Thursday on the Moon’s Malapert A region, a small crater about 300 km from the lunar south pole. Roughly the size of a red telephone box, the craft becomes the first US mission to make a soft landing on the Moon since Apollo 17 took astronauts Eugene Cernan and Harrison Schmitt to the lunar surface in December 1972.

The mission, aka IM-1, after the Houston-based company Intuitive Machines that operates it, carries an optical telescope, dubbed ILO-X, and a radio telescope called ROLSES. The two telescopes delivered by Odysseus now join one that arrived on China’s Chang’e-3 mission in 2013.

 

Battle for the skies: US insists GMT and TMT telescopes must vie for funding

06 Mar 2024

Take your pick: The National Science Foundation is set to pick between supporting the Giant Magellan Telescope or the Thirty Meter Telescope (Courtesy: US-ELTP (TIO/NOIRLab/GMTO))

The US National Science Foundation (NSF) has announced it will only support the construction of the Giant Magellan Telescope (GMT) or the Thirty Meter Telescope (TMT) – but not both facilities. The decision to pick just one next-generation, ground-based instrument came as the National Science Board (NSB), which oversees the NSF, set a limit of $1.6bn for its Extremely Large Telescope programme (US-ELTP). The board says it will discuss the NSF’s “plan to select which of its two candidate telescopes to continue to support” at its meeting in May.

Both the GMT and the TMT are seen as the future of US ground-based astronomy and stem from advances in mirror technology. The GMT will rely on seven primary and seven secondary mirrors to give it an optical surface of 25.4 m. Building is already under way at Chile’s Las Campanas peak.

 

Could gravastars be nested inside one another like a Russian doll?

18 Mar 2024

Alternative to black holes: physicists at Goethe University Frankfurt have calculated that a nested gravastar (nestar) could look like a matryoshka doll. (Courtesy: Daniel Jampolski and Luciano Rezzolla/Goethe University Frankfurt)

Gravastars, hypothetical alternatives to black holes, could end up nested inside one another like a Russian Matryoshka doll – according to new calculations that combine quantum mechanics with Einstein’s general theory of relativity. If such exotic objects exist, they could reveal their presence in gravitational-wave signals.

Black holes form by the gravitational collapse of a large star, or possibly a gas cloud, to a tiny region where gravity is so strong that not even light can escape.

 

Water observed on asteroids for the first time

27 Feb 2024

Flying high: the SOFIA telescope was carried skyward by a jumbo jet. (Courtesy: NASA/Jim Ross)

The first direct observation of water on the surface of an asteroid has been made using an airborne near-infrared telescope. Water was detected on two stony S-type asteroids, which are thought to have been born dry. The discovery could provide insights into the complex and eventful history of the solar system’s minor bodies – and in particular, how their orbits may have evolved over time.

 

Space weather phenomenon observed in the lab for the first time

21 Mar 2024 Isabelle Dumé

Observation of spontaneous chorus emission in RT-1: When the plasma confined in the dipole magnetic field of RT-1 contains a significant fraction of high-temperature electrons (red particles), a chorus emission (white emission lines) forms with a variable frequency (sound height) similar to birdsong. Courtesy: National Institute for Fusion Science

Space weather events known as whistler mode chorus emissions have been observed in the laboratory for the first time. These emissions occur naturally within regions of space dominated by planetary magnetic fields – magnetospheres – and they are related to the aurorae that light up our northern and southern skies every winter.

 

Could lasers synthesize heavy elements produced in neutron-star mergers?

19 Mar 2024 Isabelle Dumé

The experimental campaign on the neutron generation at Apollon: The inside of the target chamber showing the off-axis parabola and some diagnostics. (Courtesy: Julien Fuchs)

An astrophysical process that creates elements heavier than iron may be even more challenging to reproduce in the laboratory than was previously believed – but not impossible. This is the conclusion of researchers at the Laboratoire pour l’Utilisation des Lasers Intenses (LULI) in France, who report that reproducing conditions typically seen during neutron-star mergers will require major improvements to both proton and neutron sources. This insight is crucial, they say, because it provides a more realistic framework for future efforts to replicate stellar processes.

 

Can you solve this quantum cryptic word search?

19 Mar 2024

How well do you know your quantum physics? Find out with this fun, cryptic word search, created by Ian Randall. All answers are hidden in the grid vertically, horizontally or diagonally, with no letters skipped

As an added bonus, all of the unused letters – when read top left to bottom right – reveal a hidden message.

You can download a PDF of this puzzle. The answers will be published on 1 May on the Physics World website. Please note that this word search is just for fun; there are no prizes.

Clues

 

Wigner’s friend: the quantum thought experiment that continues to confound

18 Mar 2024 Robert P Crease

“Wigner’s friend” is a curious thought experiment that has stumped physicists and philosophers for more than 60 years. Robert P Crease, Jennifer Carter and Gino Elia advise on how to resolve this conundrum

Quantum mystery In 1961 Eugene Wigner imagined a friend doing an experiment in a lab while he waits outside. The paradox is that Wigner and the friend predict different outcomes, yet both are right. (iStock/Floriana)

The quantum world provides fertile material for thought experiments that seem so strange-but-true as to defy logic. One of the most notorious is “Wigner’s friend”, which has challenged physicists and philosophers ever since it was first conceived by the Hungarian-American physicist Eugene Wigner. He published the thought experiment in a 1961 book edited by the mathematician Irving Good entitled The Scientist Speculates: an Anthology of Partly-baked Ideas.

 

New attosecond X-ray spectroscopy technique ‘freezes’ atomic nuclei in place

13 Mar 2024 Isabelle Dumé

Scientists used a synchronized attosecond X-ray pulse pair (pictured purple and green here) from an X-ray free electron laser to study the energetic response of electrons (gold) in liquid water on the attosecond time scale, while the hydrogen (white) and oxygen (red) atoms are “frozen” in time. (Courtesy: Nathan Johnson | Pacific Northwest National Laboratory)

Scientists can now follow the movement of electrons and the ionization of molecules in real time thanks to a new attosecond X-ray spectroscopy technique. Like stop-motion photography, the technique effectively “freezes” the atomic nucleus in place, meaning that its motion does not skew the results of measurements on the electrons whizzing around it. According to the technique’s developers, it could be used not only to probe the structure of molecules, but also to track the birth and evolution of reactive species that form via ionizing radiation.

 

Magnetic microbots show promise for treating aneurysms and brain tumours

14 Mar 2024

Remote control Schematic showing (top panel) how microfibrebots can anchor to a blood vessel, navigate via helical propulsion, elongate to pass through narrow regions and aggregate to block blood flow. Potential applications (bottom panel) include coil embolization of aneurysms and tumours, and selective particle embolization of tumours. (Courtesy: Jianfeng Zang, HUST)

A team of researchers in China has developed novel magnetic coiling “microfibrebots” and used them to embolize arterial bleeding in a rabbit – paving the way for a range of controllable and less invasive treatments for aneurysms and brain tumours.

 

Cat qubits reach a new level of stability

05 Mar 2024 David Schlegel

Cat on a chip: Photograph of a chip developed at Alice and Bob that is similar to the ones used in the experiments. (Courtesy: Alice and Bob/Nil Hoppenot)

Quantum computers could surpass conventional computing in essential tasks, but they are prone to errors that ultimately lead to the loss of quantum information, limiting today’s quantum devices. Therefore, to achieve large-scale quantum information processors, scientists need to develop and implement strategies for correcting quantum errors.