Nuclear clock breakthrough in Vienna sets stage to outclass atomic time clocks

A Thorium-229 nucleus is irradiated with stabilized laser light (Laser 1). A second Laser (Laser 2) is used to probe the atomic shell's hyperfinestructure in order to determine via the change of the nuclear spin state if the nucleus was successfully excited. A photomultiplier tube (PMT) is used to probe if Laser 2 is on resonance. Based on the PMT signal Laser 1 is actively stabilized to the nuclear transition via a feedbackloop. In this way the frequency of Laser 1 will exactly match the frequency of the nuclear excitation. The frequency of Laser 1 can be accurately measured with the help of a frequency comb and therefore used as a time and frequency standard.

Vienna scientists have built the first self-stabilizing thorium nuclear clock, a prototype that could eventually outclass today’s most precise atomic clocks.

The file demonstrates the way of thinking of the entropic gravity, holographic principle, entropy distribution, and derivation of Einstein GR equations from these considerations

Quanta’s dive into AdS/CFT shows why gravity looks holographic, hinting our 3D universe could emerge from a 2D quantum boundary and what that mind-bending idea means for physics.

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Enriched uranium is uranium processed to increase the concentration of the fissile isotope uranium-235 (U-235) beyond its natural abundance of 0.7%. Fissile refers to a material—specifically a nuclide—that can undergo nuclear fission when it absorbs a low-energy (thermal) neutron. This property is crucial because only fissile materials can sustain a self-sustaining nuclear chain reaction with…

Four researchers from the Institute of Photonics at Leibniz University Hannover have created a new transmitter-receiver system for sending entangled photons through an optical fiber.

One of the most basic ideas in physics is that the different properties of mass – weight, inertia and gravitation – always stay the same in relation to each other. This is really important because if it wasn’t true, Albert Einstein’s theory of relativity would be wrong and we’d have to rewrite our physics textbooks.

The study of fluids and physics with buoyancy involves some important principles: buoyancy, fluid motion, fluid resistance, and a Reynolds number.

A group of scientists from Ohio University, Argonne National Laboratory, and the University of Illinois-Chicago, among others, led by Ohio University Professor of Physics, and Argonne National Laboratory scientist, Saw Wai Hla, have achieved a groundbreaking feat – capturing the world’s first X-ray signature of a single atom.

The energetic universe as seen with the eROSITA X-ray telescope

In the 1920s, Edwin Hubble made a groundbreaking discovery while observing distant galaxies: the universe is expanding. However, it wasn’t until 1998 that the observation of Type Ia supernovae led to the further discovery that the universe is not just expanding, but also experiencing accelerated expansion. Astrophysicist Joe Mohr from LMU explains that to account…

Have you ever experienced time slowing down or speeding up? A new study suggests that our moment-to-moment perception of time is not continuous but may stretch or shrink with each heartbeat.

Wavefunctions of the electron in a hydrogen atom at different energy levels

A recent study published in the journal Nature by researchers from the Weizmann Institute of Science introduces a new tool that makes use of the wave-particle duality of electrons.