Tag Archive for 'Vacuum'

Illustration of photon-photon scattering in the laboratory: two green petawatt lasers beams collide at the focus with a third red beam to polarise the quantum vacuum; this allows a fourth blue laser beam to be generated, with a unique direction and color, which conserves momentum and energy. Image credit: Zixin (Lily) Zhang.

Physicists Study How Light Interacts with Quantum Vacuum

Jun 5, 2025 by News Staff

Physicists have achieved the first-ever real-time, 3D simulations of how intense laser beams alter the quantum vacuum — a state once assumed to be...

Masses, sizes, and relative densities of objects in our Universe. Image credit: Charles H. Lineweaver & Vihan M. Patel, doi: 10.1119/5.0150209.

Astrophysicists Put All Objects in Universe into One Pedagogical Plot

Oct 19, 2023 by News Staff

In a new paper, astrophysicists from Australian National University present an overview of the thermal history of our Universe and the sequence of objects...

Two gold ions (red) move in opposite direction at 99.995% of the speed of light (v, for velocity, = approximately c, the speed of light). As the ions pass one another without colliding, two photons (γ) from the electromagnetic cloud surrounding the ions can interact with each other to create a matter-antimatter pair: an electron (e-) and positron (e+). Image credit: Brookhaven National Laboratory.

Physicists Produce Matter and Antimatter from Photon Collisions

Aug 11, 2021 by News Staff

Physicists with the STAR Collaboration at Brookhaven National Laboratory’s Relativistic Heavy Ion Collider (RHIC) have produced definitive evidence for...

A pure NaK drop exposed to water vapor in vacuum. Image credit: Mason et al., doi: 10.1038/s41586-021-03646-5.

Scientists Create Metallic Water Solution

Jul 30, 2021 by News Staff

Insulating materials can in principle be made metallic by applying pressure. In the case of pure water, this is estimated to require a pressure of 48 Mbars...

The Unruh effect predicts a thermal response for an accelerated detector moving through the vacuum. Gooding et al. propose an interferometric scheme to observe an analogue of the circular Unruh effect using a localized laser coupled to a Bose-Einstein condensate. Image credit: University of Nottingham.

Physicists Propose New Method for Observing Hypothetical Unruh Effect

Nov 23, 2020 by News Staff

The Unruh effect was described by Stephen Fulling in 1973, Paul Davies in 1975, and William Unruh in 1976. Sometimes called the Fulling-Davies-Unruh effect,...

Macleod et al analyzed the properties of vacuum Cherenkov radiation in strong laser pulses and the magnetic field around a pulsar. Image credit: Gerd Altmann.

High-Velocity Charged Particles Emit Cherenkov Radiation in Quantum Vacuum

May 6, 2019 by News Staff

According to new research published in the journal Physical Review Letters, charged particles traveling through empty space can emit Cherenkov radiation...

Hubble view of the galaxy cluster Abell 1689. Image credit: NASA / ESA / Hubble Heritage Team / STScI / AURA / J. Blakeslee, Dominion Astrophysical Observatory / H. Ford, JHU.

Space-Time is Constantly Moving, Physicists Say

May 15, 2017 by News Staff

A team of researchers from the Department of Physics and Astronomy at the University of British Columbia, Canada, has tackled the question ‘what causes...

An experiment proposed by Dr. Donald Chang aims at resolving divergence between special relativity and standard model of cosmology. Image credit: NASA / ESA / Hubble Heritage Team / STScI / AURA / J. Blakeslee, NRC Herzberg, DAO / H. Ford, JHU.

Is There a Resting Frame in Universe?

Mar 23, 2017 by News Staff

Physics is sometimes closer to philosophy when it comes to understanding the Universe. Dr. Donald Chang, a physicist at the Hong Kong University of Science...

This artist’s view shows how the light coming from the surface of a strongly magnetic neutron star (left) becomes linearly polarized as it travels through the vacuum of space close to the star on its way to the observer on Earth (right). The polarization of the observed light in the extremely strong magnetic field suggests that the empty space around the neutron star is subject to a quantum effect known as vacuum birefringence. The magnetic and electric field directions of the light rays are shown by the red and blue lines. Image credit: L. Calçada / ESO.

Astronomers Report First Observational Evidence for Vacuum Birefringence

Nov 30, 2016 by News Staff

By studying the light emitted from the very dense and strongly magnetic neutron star RX J1856.5-3754, a team of astronomers has found the strongest observational...