Quantum Method Closes in on Gravitational Constant - Scientific American

Quantum Method Closes in on Gravitational Constant - Scientific American; Researchers have been unable to identify the source of errors causing the disagreement in the conventional measurements. The set-up of the latest measurement is unlikely to contain the same errors as the torque method...

In the experiment described by Tino’s team, pulses of laser light tickle a cloud of rubidium atoms cooled to nearly absolute zero, driving the atoms to rise and fall like a fountain under the influence of gravity. The pulses split the 'matter wave' associated with each atom into a superposition of two energy states, each of which has a different velocity and reaches a different height — 60 or 90 centimeters — before falling back. The matter wave that rises farthest has a greater separation from the tungsten cylinders, and thus senses a slightly different gravitational pull. The difference in force imparts a measurable shift in the final state of the two matter waves when they recombine, creating an interference pattern.

When fluid dynamics mimic quantum mechanics | KurzweilAI

When fluid dynamics mimic quantum mechanics | KurzweilAI: In the experiments reported in PRE, the researchers mounted a shallow tray with a circular depression in it on a vibrating stand. They filled the tray with a silicone oil and began vibrating it at a rate just below that required to produce surface waves.

They then dropped a single droplet of the same oil into the bath. The droplet bounced up and down, producing waves that pushed it along the surface.

The waves generated by the bouncing droplet reflected off the corral walls, confining the droplet within the circle and interfering with each other to create complicated patterns. As the droplet bounced off the waves, its motion appeared to be entirely random, but over time, it proved to favor certain regions of the bath over others...

The statistical description of the droplet’s location is analogous to that of an electron confined to a circular quantum corral and has a similar, wavelike form.

'Holographic Duality' Hints at Hidden Subatomic World - Wired Science

'Holographic Duality' Hints at Hidden Subatomic World - Wired Science; If strongly correlated matter is thought of as “living” on the 2-D surface of a pond, the holographic duality suggests that the extreme turbulence on that surface is mathematically equivalent to still waters in the interior. Physicists can get at the surface-level behavior by studying the parallel, but much simpler, situation below...

In the mathematical parlance of the holographic duality, certain strongly correlated matter in 2-D corresponds, in 3-D, to a black hole.... “These very complicated quantum mechanical collective effects are beautifully captured by black hole physics... For strongly correlated systems, if you put an electron into the system, it will immediately ‘disappear’ — you can no longer track it.” It’s like an object falling into a black hole.


To determine a formula for the conductivity of cuprates, Horowitz and Santos had to study how light would interact with the complicated horizon of their black hole... In the new work, they extended the calculation down to the temperature range in which cuprates become superconductive, or conduct electricity with no resistance, and again found a close match with experimental measurements of real cuprates.

Curves in spacetime violate Heisenberg's uncertainty principle

Curves in spacetime violate Heisenberg's uncertainty principle: "Deutsch's model describes the strange quantum effects that we might see in the presence of CTCs, within a future theory of quantum gravity," Pienaar said. "However, if there are no CTCs in the universe, then we would not expect to see the effects. But since the slowing of time due to gravity looks just like the effect of an OTC from the outside, and since OTCs still lead to strange effects (as we have shown), we suggested that these effects might turn up in strong gravitational fields, even without any closed loops in time. If so, then they would allow us to violate the Heisenberg uncertainty principle and clone coherent states of light without needing a full-blown time machine.

"Of course, the connection between OTCs and gravitational fields is still very speculative and might turn out to be wrong..."

Wave-particle duality visualized in quantum movie

Wave-particle duality visualized in quantum movie: The video shows the build-up of a quantum interference pattern from stochastically arriving single phthalocyanine fluorescent-dye molecules after they traversed an ultra-thin nanograting. These represent the most massive molecules in quantum far-field diffraction so far.

The researchers used a spatially resolving fluorescence microscope whose sensitivity is so high that each molecule can be imaged and located individually with an accuracy of about 10 nanometers.

Can fluid dynamics offer insights into quantum mechanics?

Can fluid dynamics offer insights into quantum mechanics?: In Couder’s system — which Bush plans to explore further at MIT — a fluid-filled tray is placed on a vibrating surface. The intensity of the vibrations is held just below the threshold at which it would cause waves — so-called Faraday waves — on the surface of the fluid. When a droplet of the same fluid is placed on the surface, it’s initially suspended on a cushion of air. Although the surface of the fluid appears perfectly placid, the vibration of the tray flings the droplet upward before the cushion of air dissolves, and the droplet begins bouncing. The bouncing causes waves, and those waves, in turn, propel the droplet along the surface. Bush and Couder call these moving droplets “walkers.”
“One of their first experiments involved sending walkers towards a slit,” Bush says. “As they pass through the slit, they appear to be randomly deflected, but if you do it many times, diffraction patterns emerge.” That is, the droplets strike the far wall of the tray in patterns that reproduce the interference patterns of waves. “Their system is a macroscopic version of the classic single-photon diffraction experiments,” Bush says.
Wave-borne fluid droplets mimic other quantum phenomena as well, Bush says. One of these is quantum tunneling, subatomic particles’ apparent ability to pass through barriers. A walking droplet approaching a barrier across the tray will usually bounce off it, like a hockey puck off the wall. But occasionally, the droplet will take enough energy from the wave that it hops right over the barrier.