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Category: particle physics – Page 12

Gold Does Something Unexpected When Superheated Past Its Melting Point

Gold remains perfectly solid when briefly heated beyond previously hypothesized limits, a new study reports, which may mean a complete reevaluation of how matter behaves under extreme conditions.

The international team of scientists behind the study used intense, super-short laser blasts to push thin fragments of gold past a limit known as the entropy catastrophe; the point at which a solid becomes too hot to resist melting. It’s like a melting point, but for edge cases where the physics isn’t conventional.

In a phenomenon called superheating, a solid can be heated too quickly for its atoms to have time enter a liquid state. Crystals can remain intact way past their standard melting point, albeit for a very, very brief amount of time.

Atomic Vision Achieved: New Microscope Sees Light at 1-Nanometer Precision

Scientists have built a microscope capable of visualizing optical responses at the scale of individual atoms, redefining the limits of optical imaging. Scientists have created a groundbreaking microscope capable of capturing how surfaces respond to light with an exceptional resolution of just one

Simulating the Hawking effect and other quantum field theory predictions with polariton fluids

Quantum field theory (QFT) is a physics framework that describes how particles and forces behave based on principles rooted in quantum mechanics and Albert Einstein’s special relativity theory. This framework predicts the emergence of various remarkable effects in curved spacetimes, including Hawking radiation.

Hawking radiation is the thermal radiation theorized to be emitted by close to the (i.e., the boundary around a black hole after which gravity becomes too strong for anything to escape). As ascertaining the existence of Hawking radiation and testing other QFT predictions in space is currently impossible, physicists have been trying to identify that could mimic aspects of curved spacetimes in experimental settings.

Researchers at Sorbonne University recently identified a new promising experimental platform for simulating QFT and testing its predictions. Their proposed QFT simulator, outlined in a paper published in Physical Review Letters, consists of a one-dimensional quantum fluid made of polaritons, quasiparticles that emerge from strong interactions between photons (i.e., light particles) and excitons (i.e., bound pairs of electrons and holes in semiconductors).

A strange quantum battery concept reveals the second law of entanglement

For more than a century, the laws of thermodynamics have helped us understand how energy moves, how engines work, and why time seems to flow in one direction. Now, researchers have made a similarly powerful discovery, but in the strange world of quantum physics.

Scientists have shown for the first time that entanglement, the mysterious link between quantum particles, can be reversibly manipulated just like heat or energy in a perfect thermodynamic cycle.

The researchers support their findings using a novel concept called an entanglement battery, which allows entanglement to flow in and out of quantum systems without being lost, much like a regular battery stores and supplies energy.

IceCube neutrino search sets first constraints on proton fraction of ultrahigh-energy cosmic rays

Neutrinos are subatomic particles with no charge and very little mass that are known to weakly interact with other matter in the universe. Due to their weak interactions with other particles, these particles are notoriously difficult to detect.

A class of that has so far proved particularly elusive to detection methods are extremely-high-energy neutrinos, which have energies above 1016 electronvolts (eV). Physical theories suggest that these neutrinos would be produced from very energy-intensive astrophysical phenomena, such as interactions of ultrahigh-energy .

The IceCube Collaboration, a large group of researchers based at various research institutes worldwide, has been searching for extremely-high-energy neutrinos for over a decade. Their most recent findings, published in Physical Review Letters, set constraints on the proportion of protons in ultrahigh-energy cosmic rays, for the first time relying on data collected at the IceCube observatory, while also placing limits on the diffuse flux of extremely-high-energy neutrinos.

Famous double-slit experiment holds up when stripped to its quantum essentials

MIT physicists have performed an idealized version of one of the most famous experiments in quantum physics. Their findings demonstrate, with atomic-level precision, the dual yet evasive nature of light. They also happen to confirm that Albert Einstein was wrong about this particular quantum scenario.

The experiment in question is the double-slit experiment, which was first performed in 1801 by the British scholar Thomas Young to show how light behaves as a wave. Today, with the formulation of quantum mechanics, the double-slit experiment is now known for its surprisingly simple demonstration of a head-scratching reality: that light exists as both a particle and a wave. Stranger still, this duality cannot be simultaneously observed. Seeing light in the form of particles instantly obscures its wave-like nature, and vice versa.

The original experiment involved shining a beam of light through two parallel slits in a screen and observing the pattern that formed on a second, faraway screen. One might expect to see two overlapping spots of light, which would imply that light exists as particles, a.k.a. photons, like paintballs that follow a direct path. But instead, the light produces alternating bright and dark stripes on the screen, in an interference pattern similar to what happens when two ripples in a pond meet. This suggests light behaves as a wave. Even weirder, when one tries to measure which slit the light is traveling through, the light suddenly behaves as particles and the interference pattern disappears.

The Uncertainty Principle

Quantum mechanics is generally regarded as the physical theory that is our best candidate for a fundamental and universal description of the physical world. The conceptual framework employed by this theory differs drastically from that of classical physics. Indeed, the transition from classical to quantum physics marks a genuine revolution in our understanding of the physical world.

One striking aspect of the difference between classical and quantum physics is that whereas classical mechanics presupposes that exact simultaneous values can be assigned to all physical quantities, quantum mechanics denies this possibility, the prime example being the position and momentum of a particle. According to quantum mechanics, the more precisely the position (momentum) of a particle is given, the less precisely can one say what its momentum (position) is. This is (a simplistic and preliminary formulation of) the quantum mechanical uncertainty principle for position and momentum. The uncertainty principle played an important role in many discussions on the philosophical implications of quantum mechanics, in particular in discussions on the consistency of the so-called Copenhagen interpretation, the interpretation endorsed by the founding fathers Heisenberg and Bohr.

This should not suggest that the uncertainty principle is the only aspect of the conceptual difference between classical and quantum physics: the implications of quantum mechanics for notions as (non)-locality, entanglement and identity play no less havoc with classical intuitions.

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