Lifeboat Foundation

It’s another step on the road to developing quantum information processing applications: A key experiment succeeded in going beyond the previously defined limits for photon applications. Anahita Khodadad Kashi and Prof. Dr. Michael Kues from the Institute of Photonics and the Cluster of Excellence PhoenixD at Leibniz University Hannover (Germany) have demonstrated a novel interference effect. The scientists have thus shown that new color-coded photonic networks can be tapped, and the number of photons involved can be scaled. “This discovery could enable new benchmarks in quantum communication, computational operations of quantum computers as well as quantum measurement techniques and is feasible with existing optical telecommunication infrastructure,” says Kues.

The decisive experiment was successfully performed in the newly established Quantum Photonics Laboratory (QPL) of the Institute of Photonics and the Hannover Centre for Optical Technologies at Leibniz University Hannover. Anahita Khodadad Kashi succeeded in quantum-mechanically interfering independently generated pure photons with different colors, i.e., frequencies. Khodadad Kashi detected a so-called Hong-Ou-Mandel effect.

Hong-Ou-Mandel interference is a fundamental effect of quantum optics that forms the basis for many quantum information processing applications—from quantum computing to quantum metrology. The effect describes how two photons behave when they collide on a spatial beam splitter and explains the phenomenon of quantum mechanical interference.

One of the biggest challenges will be to create superpositions of diamonds that can remain stable over distances of a meter. More than four years ago researchers at Stanford University managed to separate a superposition consisting of 10000 atoms by about half a meter—the current record. “But we’re talking about doing it with diamonds that would have a billion or 10 billion atoms, and that is way more difficult,” Mazumdar says.

Many of the other technologies needed for the device—high vacuums, ultralow temperatures, precisely controlled magnetic fields—have all been achieved separately by various groups. But bringing them together will not be easy. “Just because you can juggle and ride a bike doesn’t mean you can do both at once,” Morley says.

If the device is ever built, it could transform gravitational-wave astronomy. The world’s current gravitational-wave detectors are all firmly anchored to the ground. “The only orientation LIGO can have is due to Earth’s rotation,” Bose says. A small detector such as MIMAC, on the other hand, could be pointed at any direction in the sky. And any physics lab in the world could house it. “The challenge is to get one of them working,” Bose says. “If one of them works, it would be very easy to make several more.”

A particle shower detected by the IceCube Neutrino Observatory at the very high energy of the Glashow resonance demonstrates its potential for the study of high-energy particle physics and astrophysics.

In my last post, I talked about the idea of warp drive and whether it might one day be possible. Today I’ll talk about another faster-than-light trick: wormholes.

Wormholes are an old idea in general relativity. It’s based on work by Albert Einstein and Nathan Rosen, who tried to figure out how elementary particles might behave in curved spacetime. Their idea treated particle-antiparticle pairs as two ends of a spacetime tube.

This Einstein-Rosen Bridge would look like a black hole on one end, and an anti-black hole, or white hole, on the other end.

At microscopic scales, picking, placing, collecting, and arranging objects is a persistent challenge. Advances in nanotechnology mean that there are ever more complex things we’d like to build at those sizes, but tools for moving their component parts are lacking.

Now, new research from the University of Pennsylvania’s School of Engineering and Applied Science shows how simple, microscopic robots, remotely driven by magnetic fields, can use capillary forces to manipulate objects floating at an oil-water interface.

This system was demonstrated in a study published in the journal Applied Physics Letters on January 28, 2020.

A new type of maser made from periodically driven xenon atoms can detect low frequency magnetic fields far better than any previous magnetometer, according to scientists in China and Germany. The researchers believe their device is ready for use in a proposed gravitational wave search and might in future be used to find hypothetical dark matter particles.

Masers are the microwave-wavelength equivalent of lasers and their extreme frequency stability allows them to make invaluable contributions to atomic clocks, radio telescopes and several other areas of physics. In a traditional maser – as in a traditional laser – the masing action occurs between two energy levels in an atomic or molecular gain medium confined in a cavity. As electromagnetic radiation bounces back and forth in the cavity, photons whose frequency is resonant with the energy difference between the two levels are repeatedly emitted and absorbed by the atoms. Eventually, a “population inversion” with more atoms in the upper level is achieved, and stimulated emission from these atoms produces a highly monochromatic beam of microwave radiation.

When physicists need to understand the quantum mechanics that describe how atomic clocks work, how your magnet sticks to your refrigerator or how particles flow through a superconductor, they use quantum field theories.

When they work through problems in quantum field theories, they do so in “imaginary” time, then map those simulations into real quantities. But traditionally, these simulations nearly always include uncertainties or unknown factors that could cause equation results to be “off.” So, when physicists interpret their simulation results into real quantities, these uncertainties amplify exponentially, making it difficult to have confidence that their results are as accurate as necessary.

Now, a pair of University of Michigan physicists have discovered that a set of functions called the Nevanlinna functions can tighten the interpretation step, showing that physicists may be able to overcome one of the major limitations of modern quantum simulation. The work, published in Physical Review Letters, was led by U-M physics undergraduate student Jiani Fei.

But that’s nothing compared to how long scientists have been waiting to spot the bizarre phenomenon. Live Science notes that Stephen Glashow first came up with the notion of the subatomic cascade back in 1960 and that it’s been a matter of pure theory that whole time.

The actual cascade of Glashow resonance involves an antineutrino — or even a regular neutrino — crashing into an electron with so much energy that it produces a comparatively-large particle called a W boson.

Doing this requires the extremely-tiny antineutrino to carry 6.3 petaelectronvolts, or the amount of energy of 6.3 quadrillion electrons accelerated by a single volt. That’s the same, Live Science calculated, as 6300 mosquitos traveling at one mile per hour — or one mosquito traveling 8.2 times the speed of sound.

Physicists exploring the quantum world watched the birth of a quasiparticle, shedding light on the strange behavior of these strange “fake particles.”