Resolving A Quantum Paradox with The Atomic Knights

"For nearly a century, the widespread interpretation of quantum mechanics suggests that everything is uncertain until it is observed, and that observation inevitably alters reality," says Professor Steinberg. "However, in the 1990s, a technique known as 'interaction-free measurement' seemed to promise the ability to 'see without looking’. But when Lucien Hardy proposed that one could never reliably make inferences about past events which hadn't been directly observed, a paradox emerged which suggested that whenever one attempted to reason about the past in this way they would be led into error.

Scientists have now combined Hardy's Paradox with a new theory known as weak measurement showing that in one sense, one can indeed talk about the past, resolving the paradox. Weak measurement is a tool whereby the presence of a detector is less than the level of uncertainty around what is being measured, so that there is an imperceptible impact on the experiment.

"We found that all of the seemingly paradoxical conclusions in Hardy's Paradox can, in fact, be experimentally verified," says Steinberg, "but that the use of weak measurement removes the contradiction."

"Until recently, it seemed impossible to carry out Hardy's proposal in practice, let alone to confirm or resolve the paradox," he says. "We have finally been able to do so, and to apply Aharonov's methods to the problem, showing that there is a way, even in quantum mechanics, in which one can quite consistently discuss past events even after they are over and done. Weak measurement finds what is there without disturbing it." link

Ref: Experimental Joint Weak Measurement on a Photon Pair as a Probe of Hardy's Paradox. 2009. J. S. Lundeen and A. M. Steinberg. Phys. Rev. Lett. 102, 020404 (2009)

Strange Adventures #141 (June, 1962). Atomic Knights © DC Comics
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Worn This Day (1797): First Top Hat

Art by Art Adams

In 1797, the top hat was first worn in England by James Heatherington, a Strand haberdasher in London. An issue of the Times of that period records that when he left his shop with his extraordinary headwear, a crowd of onlookers assembled, which degenerated into a shoving match. Heatherington was summoned to appear in court before the Lord Mayor and fined £50 for going about in a manner "calculated to frighten timid people."

Within a month, he was overwhelmed with orders for the new top hats. link

Zatanna © DC Comics

Professor Eureka

© DC Comics

Solved: The Mystery of The Walking Martian Rocks

Rocks on Mars are on the move, rolling into the wind and forming organized patterns, according to new research.

Images taken by the Mars Exploration Rover Spirit show small rocks regularly spaced about 5 to 7 cm apart on the intercrater plains between Lahontan Crater and the Columbia Hills.

The new finding counters the previous explanation of the evenly spaced arrangement of small rocks on Mars. That explanation suggested the rocks were picked up and carried downwind by extreme high-speed winds thought to occur on Mars in the past.

Pelletier and his colleagues suggest that wind blows sand away from the front of the rock, creating a pit, and then deposits that sand behind the rock, creating a hill. The rock then rolls forward into the pit, moving into the wind, he said. As long as the wind continues to blow, the process is repeated and the rocks move forward.

These Spirit Rover camera images of the intercrater plain between Mars' Lahontan Crater show uniformly-spaced small rocks, known as clasts. Credit: GSA

The process is nearly the same with a cluster of rocks. However, with a cluster of rocks, those in the front of the group shield those in the middle or on the edges from the wind. Because the middle and outer rocks are not directly hit by the wind, the wind creates pits to the sides of those rocks. Therefore, they roll to the side, not directly into the wind, and the cluster begins to spread out.

Pelletier plans to apply the same models to larger features on Mars such as sand dunes and wind-sculpted valleys and ridges called "yardangs." press release

Ref.: Wind-Driven Reorganization of Coarse Clasts on the Surface of Mars. 2008. Geology

NASA Mars Exploration Rover Mission

Aquaman, Microbe Hunter!

Adventure Comics #200 (May 1954). Aquaman © DC Comics

Announced This Day: Discovery of X-Rays

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In 1896, German scientist, Wilhelm Röntgen announced his discovery of x-rays. He sent copies of his manuscript and some of his x-ray photographs to several renowned physicists and friends, including Lord Kelvin in Glasgow and Henre Poincare in Paris. Four days later, on 5 Jan 1896, Die Presse published the news in a front-page article which described the discovery and suggested new methods of medical diagnoses might be made with this new kind of radiation. link

'X'-The Man With X-Ray Eyes

Seeing The Quantum World

RBCC #149 (1977) Art by Mike Zeck. Captain Action © DC Comics

The Quantum Information Science center at the U of Calgary has produced a four-minute animated intended to help people see how a quantum computer would work and its underlying science.

"The animation incorporates state-of-the-art techniques to show the science and the technology in the most accurate and exciting way possible while being true to the underlying principles of quantum computing," says Sanders.

"There is a history of simple visualization over the last century to convey quantum concepts," says Sanders. He notes that Erwin Schrödinger introduced his eponymous cat, which is left in a tragic state of being in a superposition of life and death, an illustration of the strangeness of quantum theory. And the uncertainty principle associated with Werner Heisenberg and his fictional gamma ray microscope, has found its way into common English parlance.

"The imagery of the early days of quantum mechanics played a crucial role in understanding and accepting quantum theory. Our work takes this imagery a quantum leap forward by using the state-of-the-art animation techniques to explain clearly and quickly the nature of quantum computing which is, by its very nature, counterintuitive." link

Watch the spin-up scene: the quantum information encoded on the electron spin transforms smoothly between zero and one poles—the quantum analogue of a NOT gate.

Watch more clips HERE.

Ref: Visualizing a silicon quantum computer. 2008. B.C. Sanders, et al. New J. Phys. 10 125005 (20pp).