Fundamental Principle of Physics

A new study has overturned a fundamental principle of physics by demonstrating that similarly charged particles can attract each other in a solution, with the effect varying between positive and negative charges depending on the solvent. This discovery has significant implications for various scientific processes, including self-assembly and crystallization. 

The research reveals the importance of solvent structure at the interface in determining interparticle interactions, challenging long-held beliefs and indicating a need for a re-evaluation of our understanding of electromagnetic forces. Credit: Zhang Kang


“Opposites charges attract; like charges repel” is a fundamental principle of basic physics. However, a new study from Oxford University, recently published in the journal Nature Nanotechnology, has demonstrated that similarly charged particles in solution can, in fact, attract each other over long distances.

Just as surprisingly, the team found that the effect is different for positively and negatively charged particles, depending on the solvent.  READ MORE...

A New Phase of Matter

Physicists have discovered a new phase of matter, the “chiral bose-liquid state.” This state, discovered through the exploration of kinetic frustration in quantum systems, exhibits robust properties such as unchangeable electron spin and long-range entanglement. The discovery, requiring high magnetic fields for observation, expands our understanding of the physical world and could have applications in fault-tolerant digital data encoding.

For Experimental Physicists, Quantum Frustration Leads to Fundamental Discovery
“Chiral bose-liquid state” is a new phase of matter, according to UMass Amherst professor.

A team of physicists, including University of Massachusetts assistant professor Tigran Sedrakyan, recently announced in the journal Nature that they have discovered a new phase of matter. Called the “chiral bose-liquid state,” the discovery opens a new path in the age-old effort to understand the nature of the physical world.

Under everyday conditions, matter can be a solid, liquid, or gas. But once you venture beyond the everyday—into temperatures approaching absolute zero, things smaller than a fraction of an atom or which have extremely low states of energy—the world looks very different. “You find quantum states of matter way out on these fringes,” says Sedrakyan, “and they are much wilder than the three classical states we encounter in our everyday lives.”

Sedrakyan has spent years exploring these wild quantum states, and he is particularly interested in the possibility of what physicists call “band degeneracy,” “moat bands” or “kinetic frustration” in strongly interacting quantum matter.  READ MORE...

How Flat Can it Get?

An artist’s conception of the seven planets in the TRAPPIST-1 system which orbit the star in an exceptinally flat plane. Astronomers have used the extreme flatness of the system to constrain the properties and evolution of the protoplanetary disk. Credit: NASA and JPL/Caltech

The planets of the solar system all orbit the Sun more-or-less in a plane. Compared to the Earth’s orbit, which defines the plane at zero degrees, the orbit with the largest angle is Mercury’s whose inclination is 7 degrees (the angle of the orbit of the dwarf planet Pluto is 17. 2 degrees). 

The orbital characteristics of planets evolve as the protoplanetary disk of gas and dust dissipates, and as the young planets themselves migrate in the disk in response to their mutual gravitational influences and effects of material in the disk. Astronomers recognize therefore that the orbital appearance of a planetary system reflects its evolutionary story.

The planetary system TRAPPIST-1 consists of seven Earth-sized planets orbiting a small star (a mass of only .09 solar-masses) about forty light-years from the Sun. First detected by the TRAPPIST telescopes, follow-up observations with the IRAC camera on Spitzer and the K2 mission, among others, have by now determined the planetary masses to precisions between 5-12% and refined other properties of the system. 

Remarkably, the system is by far the flattest known: its orbital inclination is only 0.072 degrees. This extreme flatness is potentially a very important constraint on the formation and evolution of the system. The system is also very compact with the most distant of its seven planets orbiting only .06 astronomical units from the star (in our solar system, Mercury orbits more than five times farther away). In such a closely packed configuration the planets’ mutual gravitational attractions will be particularly important influences on details like the orbital inclinations.

CfA astronomers Matthew Heising, Dimitar Sasselov, Lars Hernquist, and Ana Luisa Tió Humphrey used 3-D computer simulation of the gaseous disk and planets to study a range of possible formation models including several that had been suggested in previous studies.

Knowing that the gaseous protostellar disk influences the migration properties of the planets, the scientists were also particularly interested in exploring what the minimum disk mass could have been for the TRAPPIST-1 system. They adapted the computer code AREPO, which has been used successfully in the past primarily for cosmological simulations.  READ MORE...

Physics Mystery Solved

Technion researchers have found an effective solution to the famous age-old, three-body problem in physics.

The three-body problem is one of the oldest problems in physics: it concerns the motions of systems of three bodies – like the Sun, Earth, and the Moon – and how their orbits change and evolve due to their mutual gravity. The three-body problem has been a focus of scientific inquiry ever since Newton.

When one massive object comes close to another, their relative motion follows a trajectory dictated by their mutual gravitational attraction, but as they move along, and change their positions along their trajectories, the forces between them, which depend on their mutual positions, also change, which, in turn, affects their trajectory et cetera. For two bodies (e.g. like Earth moving around the Sun without the influence of other bodies), the orbit of the Earth would continue to follow a very specific curve, which can be accurately described mathematically (an ellipse).

However, once one adds another object, the complex interactions lead to the three-body problem, namely, the system becomes chaotic and unpredictable, and one cannot simply specify the system evolution over long time-scales. Indeed, while this phenomenon has been known for over 400 years, ever since Newton and Kepler, a neat mathematical description for the three-body problem is still lacking.

Star orbits in a three-body system. Credit: Technion

In the past, physicists – including Newton himself – have tried to solve this so-called three-body problem; in 1889, King Oscar II of Sweden even offered a prize, in commemoration of his 60th birthday, to anybody who could provide a general solution. In the end, it was the French mathematician Henri Poincaré who won the competition. He ruined any hope for a full solution by proving that such interactions are chaotic, in the sense that the final outcome is essentially random; in fact, his finding opened a new scientific field of research, termed chaos theory.  READ MORE...

Quantum Physics and Consciousness

One of the most important open questions in science is how our consciousness is established. 

In the 1990s, long before winning the 2020 Nobel Prize in Physics for his prediction of black holes, physicist Roger Penrose teamed up with anesthesiologist Stuart Hameroff to propose an ambitious answer.

They claimed that the brain’s neuronal system forms an intricate network and that the consciousness this produces should obey the rules of quantum mechanics – the theory that determines how tiny particles like electrons move around. 

This, they argue, could explain the mysterious complexity of human consciousness.

Penrose and Hameroff were met with incredulity. Quantum mechanical laws are usually only found to apply at very low temperatures. 

Quantum computers, for example, currently operate at around -272°C. At higher temperatures, classical mechanics takes over. Since our body works at room temperature, you would expect it to be governed by the classical laws of physics. 

For this reason, the quantum consciousness theory has been dismissed outright by many scientists – though others are persuaded supporters.

Instead of entering into this debate, I decided to join forces with colleagues from China, led by Professor Xian-Min Jin at Shanghai Jiaotong University, to test some of the principles underpinning the quantum theory of consciousness.  READ MORE

Dopamine

Neuroscientists show that mice can learn to manipulate random dopamine impulses for reward.

From the thrill of hearing an ice cream truck approaching to the spikes of pleasure while sipping a fine wine, the neurological messenger known as dopamine has been popularly described as the brain’s “feel good” chemical related to reward and pleasure.

A ubiquitous neurotransmitter that carries signals between brain cells, dopamine, among its many functions, is involved in multiple aspects of cognitive processing. 

The chemical messenger has been extensively studied from the perspective of external cues, or “deterministic” signals. Instead, University of California San Diego researchers recently set out to investigate less understood aspects related to spontaneous impulses of dopamine. 

Their results, published on July 23, 2021, in the journal Current Biology, have shown that mice can willfully manipulate these random dopamine pulses.  READ MORE

Just 35 Light Years Away

Astronomers have discovered thousands of exoplanets — planets beyond our solar system — but few have been directly imaged, because they are extremely difficult to see with existing telescopes.

A University of Hawaiʻi Institute for Astronomy (IfA) graduate student has beaten the odds and discovered a directly imaged exoplanet, and it’s the closest one to Earth ever found, at a distance of only 35 light years

Using the COol Companions ON Ultrawide orbiTS (COCONUTS) survey, IfA graduate student Zhoujian Zhang and a team of astronomers, Michael Liu and Zach Claytor (IfA), William Best (University of Texas at Austin), Trent Dupuy (University of Edinburgh) and Robert Siverd (Gemini Observatory/National Optical-Infrared Astronomy Research Laboratory) identified a planet about six times the mass of Jupiter. 

The team’s research, published in The Astrophysical Journal Letters, led to the discovery of the low-temperature gas-giant planet orbiting a low-mass red dwarf star, about 6,000 times farther than the Earth orbits the Sun. They dubbed the new planetary system COCONUTS-2, and the new planet COCONUTS-2b.

“With a massive planet on a super-wide-separation orbit, and with a very cool central star, COCONUTS-2 represents a very different planetary system than our own solar system,” Zhang explained. The COCONUTS survey has been the focus of his recently-completed PhD thesis, aiming to find wide-separation companions around stars of all different types close to Earth.  READ MORE