Information may seem ethereal, given how easily we forget phone numbers and birthdays. But scientists say it is physical, and if a new study is correct, that goes for quantum systems, too.

Although pages of text or strings of bits seem easily erased with the press of a button, the act of destroying information has tangible physical impact, according to a principle proposed in 1961 by physicist Rolf Landauer. Deleting information is associated with an increase in entropy, or disorder, resulting in the release of a certain amount of heat for each erased bit. Even the most efficient computer would still output heat when irreversibly scrubbing out data.
This principle has been verified experimentally for systems that follow the familiar laws of classical physics. But the picture has remained fuzzy for quantum mechanical systems, in which particles can be in multiple states at once and their fates may be linked through the spooky process of quantum entanglement.

Now a team of scientists reports April 13 in Proceedings of the Royal Society A that Landauer’s principle holds even in that wild quantum landscape. “Essentially what they’ve done is test [this principle] at a very detailed and quantitative way,” says physicist John Bechhoefer of Simon Fraser University in Burnaby, Canada, who was not involved with the research. “And they’re showing that this works in a quantum system, which is a really important step.” Testing Landauer’s principle in the quantum realm could be important for understanding the fundamental limits of quantum computers, Bechhoefer says.

To verify Landauer’s principle, the researchers used a system of three qubits — the quantum version of the bits found in a typical computer — made from trifluoroiodoethylene, a molecule which has three fluorine atoms. The nuclei of these three fluorine atoms have a quantum property known as spin. That “spin” can be clockwise or counterclockwise, serving the same purpose as a 0 or 1 for a standard bit.

The first qubit, which researchers called the “system,” contains the information to be erased. According to Landauer’s principle, when the information is erased, heat will be generated and energy will flow to the second qubit, known as the “reservoir.” Just as computer scientists can perform operations on the bits in a typical computer (adding or subtracting numbers, for instance), the researchers can apply operations to the fluorine qubits by using pulses of radio waves to tweak the nuclear spins.

But making measurements of quantum systems is tricky, says physicist Lucas Céleri of Federal University of Goiás in Brazil, a leader of the research team. “In a quantum world, every time you measure the system, you interact with it,” thereby changing it. So the researchers used a work-around. The third qubit is coupled to the reservoir and can be used to measure the heat generated without mucking up the qubits of interest.
When the researchers erased information, they found heat was generated as expected from Landauer’s principle. They looked at the average of multiple measurements, because quantum fluctuations mean that any single trial won’t necessarily conform to the principle. “It’s a very nice demonstration of Landauer’s principle in a quantum system, cleverly conceived and well carried out,” says quantum physicist Seth Lloyd of MIT, who was not involved with the research.

But some researchers suggest there is more work to be done. “It is a carefully executed experiment with three interacting qubits,” physicists Jukka Pekola of Aalto University in Finland and Jonne Koski of ETH Zurich wrote in an e-mail. But in a traditional test of Landauer’s principle, the reservoir would not be a single qubit, but a large “heat bath” of many particles. The researchers therefore had to account for additional entropy introduced as a result of their single-particle reservoir. The next step, Pekola and Koski say, would be to investigate a qubit that interacts with a reservoir consisting of more particles to perform a more conventional test of Landauer’s principle at the quantum level.

Some researchers believe that when memories are called to mind, they enter a fragile, wobbly state during which they are vulnerable to being weakened or changed. One way to erode old memories is to learn something new just after recalling the older memory, scientists reported in 2003 (SN: 10/11/2003, p. 228).

But that result itself is wobbly, scientists report April 25 in the Proceedings of the National Academy of Sciences. In an attempt to replicate the original finding, experimental psychologist Tom Hardwicke of University College London and colleagues didn’t see any memory alterations in people who learned a new sequence of finger taps shortly after recalling an old sequence. Nor did the researchers turn up signs of this memory interference in other tests.

The new study focused specifically on new learning, but the findings cast suspicion on the legitimacy of other ways to interfere with people’s memories, Hardwicke says. Approaches such as brain stimulation or drugs might also be flawed, the researchers argue.

An amber collector in Germany has spotted the ancient remains of a beetle never before seen in the fossil record.

Two itty-bitty specimens, entombed in amber since the middle Eocene epoch some 54.5 million to 37 million years ago, represent a new species of Jacobson’s beetle, researchers report online March 28 in the Journal of Paleontology. The beetles, Derolathrus groehni, are, like their modern relatives, about as long as the width of a grain of rice.

MicroCT scans and other images revealed narrow bodies, a shiny brown exterior and two wispy featherlike wings protruding from the hindquarters, angled like the blades of a helicopter. The fossils look just like today’s Jacobson’s beetles, says study coauthor Chenyang Cai of the Chinese Academy of Sciences.

Fringed, eyelashlike wings may have helped the beetles ride the wind, eventually spreading to far-flung regions of the world — from western Russia (a big source of Baltic amber) to distant habitats in Fiji, Sri Lanka and even Alabama, where Jacobson’s beetles have been spotted recently.

Echidnas are some of the oddest animals you’ll ever see, more closely related to a platypus than anything else, as the only other mammals that lay eggs. There are four living species: Short-beaked echidnas — about the size of a house cat and covered in spikes — are common throughout Australia and in Papua New Guinea, where three long-beaked species live.

One of those species, the western long-beaked echidna, which is larger and has fewer spines than the short-beaked variety, used to live in Australia. Scientists have found fossils of the species, and aboriginal people who lived near Darwin in north central Australia painted the echidnas on rocks more than 10,000 years ago. The long-beaked echidnas then disappeared sometime after that, scientists have thought.

There are hints, though, that the species still exists in Australia. In 2012, Kristofer Helgen of the Smithsonian National Museum of Natural History and colleagues reported in Zookeys that an echidna skull and skin housed in the National History Museum in London belonged to a western long-beaked echidna collected by John Thomas Tunney, who gathered specimens for the Western Australian Museum in Perth at the turn of the last century.
According to the specimen’s tags, Tunney had collected the animal on November 20, 1901, at Mount Anderson in the Western Kimberley region of Australia. Originally identified as a short-beaked echidna, museum scientists decided it was a Zaglossus bruijnii , a western long-beaked echidna, after removing and examining the animal’s skull. They then put the skull and skin away in a drawer; the animal was forgotten for decades until Helgen happened upon it. He and his team then examined specimen and decided that, yes, it was indeed a western long-beaked echidna. And, after examining the documentation attached to the animal’s remains, they determined that the echidna wasn’t mislabeled; it had most likely had been collected by Tunney in Australia. Perhaps the species was still living on the continent, they posited.
That wasn’t their only evidence. The researchers also recounted the tale of an encounter that one member of the team, James Kohen of Macquarie University in Australia, had with an aboriginal woman in the Kimberley region in 2001: While walking together, they noticed some poop, which the woman correctly identified as belonging to an echidna. She then told the scientist that her grandmothers “used to hunt the other one,” a much larger echidna that had not been seen for ages. Perhaps that meant that the woman’s actual grandmothers had hunted long-beaked echidnas — or maybe it was a tale told over many generations, and it was long-ago ancestors. Or maybe no one hunted long-beaked echidnas at all.
“We realize that, despite our conclusions,” the team writes, “others may remain skeptical of this Zaglossus specimen’s association with Tunney’s tags. Additional studies of this remarkable specimen might include analyses of ancient DNA, stable isotopes, and trace elements to test its origins and the context of its collection.”

To truly confirm that the long-beaked echidna is roaming modern-day Australia, scientists would have to find the animals in Australia. Though maybe not, biologist Adrian Burton notes in the April Frontiers in Ecology and the Environment.

Tunney never found a second echidna specimen; if he had, it would have been in the museum because he was contracted to supply them with one. But finding it would have been a huge undertaking, Burton writes. “To acquire a second specimen, Tunney would have been doomed to work for hours on end, laying traps and seeking out the shuffling creature among the rocky gullies and evergreen rainforest patches around [Mount] Anderson. And he may never have come any closer than stumbling upon a few scats.”

Today, though, those scats would be all researchers would need, Burton suggests. They could compare the DNA in the echidna poop to the DNA of animals living in New Guinea and genetic material gathered from the specimen in the London museum. If they all matched, then that would be proof that the species still lives in Australia.

No scientists have managed to get funding, however, for an expedition to the region where Tunney collected his echidna, Burton notes. That probably shouldn’t be all that surprising. The evidence that the long-beaked echidna lives in Australia today is pretty iffy, and the country has experienced severe cuts in funding for science in recent years. Echidna enigmas aren’t a priority.

But perhaps, just perhaps, these spiky, worm-eating creatures are still hiding out in some forest, waiting for someone to find them — or at least their poop.

In the backwaters of the solar system beyond Pluto, lies the dwarf planet Makemake. And the tiny world has an even tinier moon, NASA announced April 26. The moon was spotted as a dark smudge orbiting Makemake in April 2015 images from the Hubble Space Telescope.

Researchers estimate that the moon, temporarily dubbed S/2015 (136472) 1, is roughly 160 kilometers wide; its home world, by comparison, is about 1,400 kilometers across. The satellite appears to trek around Makemake once every 12 days or more, though more observations are needed to nail down its orbit. The moon’s motion can help researchers determine the mass of Makemake, one of the largest known bodies in the Kuiper belt.