Wanted: Large Litterbox

•May 10, 2017 • Leave a Comment


“‘The idea of the experiment was proposed in 2003 by the group of Professor Timothy Ralph of the University of Queensland, Australia. In essence, we cause interference of two ‘cats’ on a beam splitter. This leads to an entangled state in the two output channels of that beam splitter. In one of these channels, a special detector is placed. In the event this detector shows a certain result, a ‘cat’ is born in the second output whose energy is more than twice that of the initial one.’

The Lvovsky group tested this method in the lab. In the experiment, they successfully converted a pair of negative squeezed ‘Schrodinger cats’ of amplitude 1.15 to a single positive ‘cat’ of amplitude 1.85. They generated several thousand such enlarged ‘cats’ in their experiment.”

Physicists breeding Schroedinger cat states – Phys.org


Challenging Time Translation Invariance

•May 5, 2017 • Leave a Comment


“In this work, we show that quantum mechanical and gravitational properties of the clocks put fundamental limits to the joint measurability of time as given by clocks along nearby world lines. As a general feature, a quantum clock is a system in a superposition of energy eigenstates. Its precision, understood as the minimal time in which the state evolves into an orthogonal one, is inversely proportional to the energy difference between the eigenstates. Due to the mass–energy equivalence, gravitational effects arise from the energies corresponding to the state of the clock. These effects become nonnegligible in the limit of high precision of time measurement. In fact, each energy eigenstate of the clock corresponds to a different gravitational field. Because the clock runs in a superposition of energy eigenstates, the gravitational field in its vicinity, and therefore the space–time metric, is in a superposition. We prove that, as a consequence of this fact, the time dilation of clocks evolving along nearby world lines is ill-defined.We show that this effect is already present in the weak gravity and slow velocities limit, in which the number of particles is conserved. Moreover, the effect leads to entanglement between nearby clocks, implying that there are fundamental limitations to the measurability of time as recorded by the clocks.”

Entanglement of quantum clocks through gravity – PNAS

“Reality is merely an illusion, albeit a very persistent one.” – Einstein

•April 24, 2017 • 2 Comments


“‘Philosophy and Predictive Processing’ focuses entirely on the influential theory in its title, which argues that our brains are constantly making predictions about what’s out there (a flower, a tiger, a person) and these predictions are what we perceive.

To make more accurate predictions, our brains modify their internal models of the world or force our bodies to move, so that the external environment comes in line with predictions. This idea unifies perception, action and cognition into a single framework.

Some of the titles of the papers are playful, and maybe a tad over-the-top: ‘How to entrain your evil demon’, ‘How to knit your own Markov blanket’ or ‘Of Bayes and Bullets’. But despite the titles, the content is serious and heavy-going: it’s written by some well-known proponents of predictive processing, including Andy Clark, based at the University of Edinburgh, UK, and Jakob Hohwy, at Monash University, Australia.”

A guide to why your world is a hallucination – New Scientist

Coming Soon: Marty McQuantum

•April 17, 2017 • Leave a Comment


“The researchers calculated that firing a short laser pulse at graphene could instantaneously trigger a ‘population reversal,’ switching electrons to holes and vice versa. This inversion of behavior is ‘effectively a propagation back in time,’ Richter said. Such a quantum time mirror could be made with current state-of-the-art technology, the researchers added.

Although the work is not intended to test the limits of time reversal, such fundamental restrictions may appear ‘once the experimental drawbacks are surmounted one by one,’ said quantum physicist Horacio Pastawski at the National University of Córdoba in Argentina, who did not participate in this study. He noted his own research explores how time reversal may become impossible once a system becomes complex and chaotic enough.

Richter stressed this quantum time mirror only works for relatively tiny systems protected from environmental disturbances. ‘It’s completely impossible to reverse time this way with, say, a person,’ he said. ‘Still, an interesting future direction one may ask is how large a system could be made that can experience reversal with a quantum time mirror.'”

Zaps from a Laser Could ‘Reverse Time’ on the Quantum Scale – Inside Science

Alice and Bob: The Cliffhanger Question

•April 10, 2017 • Leave a Comment


“The equation is deceptively simple: ER = EPR.

It’s not made up of numerical values, but instead represents the names of some key players in theoretical physics.

On the left side of the equation, the ER stands for Einstein and Nathan Rosen,and refers to a 1935 paper they wrote together describing wormholes, known technically as Einstein-Rosen bridges.

On the right side of the equation, EPR stands for Einstein, Rosen and Boris Podolsky, who co-wrote another paper that year describing quantum entanglement.”

This New Equation Could Unite The Two Biggest Theories in Physics – Futurism

Side Effects May Vary

•April 5, 2017 • Leave a Comment


“’We know from very precise supernova observations that the universe is accelerating, but at the same time we rely on coarse approximations to Einstein’s equations which may introduce serious side-effects, such as the need for dark energy, in the models designed to fit the observational data.’

To test this the researchers constructed a computer simulation to compare a standard cosmological model (with normal matter, dark energy, and the equally mysterious dark matter) with one that only had dark matter and normal matter. The requirement was that the latter one, known as the Avera (Average Expansion Rate Approximation) model, has the same critical density as the standard model.

The simulations show a good agreement between each other and between the observations both in the early and recent universe. The Avera model does actually better match the apparent discrepancy between the local and past expansion rates of the universe.”

Dark Energy May Not Actually Exist – IFLScience!

… and stay out!

•March 23, 2017 • Leave a Comment

Galaxy with an ejected supermassive black hole

“Researchers estimate that it took the equivalent energy of 100 million supernovas exploding simultaneously to jettison the black hole. The most plausible explanation for this propulsive energy is that the monster object was given a kick by gravitational waves unleashed by the merger of two hefty black holes at the center of the host galaxy.

… Hubble’s observations of the wayward black hole surprised the research team. ‘When I first saw this, I thought we were seeing something very peculiar,’ said team leader Marco Chiaberge of the Space Telescope Science Institute (STScI) and Johns Hopkins University, in Baltimore, Maryland. ‘When we combined observations from Hubble, the Chandra X-ray Observatory, and the Sloan Digital Sky Survey, it all pointed towards the same scenario. The amount of data we collected, from X-rays to ultraviolet to near-infrared light, is definitely larger than for any of the other candidate rogue black holes.'”

Gravitational wave kicks monster black hole out of galactic core – Phys.org