Majorana fermions might be the sole component of the dark matter in our Universe

The find is the culmination of decades of research. First theorized by Italian physicist Ettore Majorana in 1937 by building on the work of Erwin Schrödinger and Paul Dirac, the Majorana fermion emitted too weak a signal to be spotted within most materials. Recently, however, theoretical physicists have suggested that some exotic materials might circumvent defects and impurities found elsewhere and allow for the detection of this elusive particle.

Building on this knowledge, Kouwenhoven connected indium antimonide nanowires to a circuit with a gold contact at one end and a slice of superconductor at the other, and then exposed the circuit to a moderate magnetic field. Measurements of the electrical conductance of the nanowires showed a peak at zero voltage that is consistent with the formation of a pair of Majorana particles.

Conceptual close-up of the Majorana nano-device

This special kind of fermion has the unique property of being its own antiparticle. An antiparticle is defined as a subatomic particle having the same mass as a given particle, but opposite electric or magnetic properties – for instance, the antiparticle of a negatively-charged electron is a positively-charged positron. The unique properties of Majorana fermions generate an interesting behavior whenever two particles interact.

Elementary particles come in two kinds: bosons, such as photons, and fermions, such as electrons. Besides having different charge and spin properties, they also behave quite differently when two particles of the same kind interact with each other.

When two bosons trade places, there is no change in their quantum mechanical state, and they become interchangeable; when two normal fermions trade places, the sign of their mathematical "wavefunction" changes from positive to negative with each switch, returning to their original state after two switches. Majorana fermions, on other hand, "remember" their previously taken path.

This property makes Majorana fermions a very strong candidate for use in quantum computers. While we’ve seen a number of developments in quantum computing in recent years, from qubits in semiconductors to manipulating quantum informationthrough electrical fields, one longstanding issue is that the qubits – "quantum bits," the basic unit of information in a quantum computer – are unstable and highly sensitive to external influences.

Not so with this particle, which promises to be unaffected by external influences (even though, it should be pointed out, it’s not yet entirely clear whether qubits created in this manner will be long-lived enough to be used in that way).

More broadly, the "memory" of these particles could be a crucial factor that will enable researchers to more effectively crack some of the long-standing mysteries of quantum mechanics once and for all, helping to investigate the behavior of other particles.

Also, as some researchers suggest, the particles may play a crucial role in cosmology – a proposed theory assumes that the mysterious dark matter, which is thought to form around 73 percent of our Universe, is composed entirely of Majorana fermions.

The video below illustrates the process by which Kouwenhoven’s team managed to isolate the fermions.

Four Particles

The head-scratcher is: the measurement is made before the decision is made, and it is accurate. "Classical correlations can be decided after they are measured," says Xiao-song Ma, the writer of the study. Entanglement can be created "after the entangled particles have been measured and may no longer exist."

The finding can be integrated into potential quantum computers, one hopes. Causality, clearly, is a quaint, irrelevant concept.

Edwin Hubble first observed this phenomenon in 1929, when he noticed that the light from distant galaxies shifted to the red end of the spectrum, as though it had been stretched as it traveled through space. By measuring the wavelengths of the light, Hubble observed that galaxies were expanding away from each other at a rate proportional to their distance from one another.

In the beginning, the universe was a single point. Where was that? It was, and still is, everywhere. Scientists even have proof: Light from the big bang, in the form of cosmic radiation, fills the sky in every direction.

Enceladus and its Plumes of Water

A new assessment by the Space Science Board looks at which destinations are most in need of protection from microbes — Europa, Enceladus, Titan, and Triton, it concludes — and sets out a series of protocols for deciding how and where best to assess and deal with the risk.

COSPAR [Committee on Space Research] guidelines require that less than 1 in 10,000 missions will deliver a single viable microbe that is able to grow on a solar system destination, i.e., a 10^-4 probability of contamination per mission flown. Failure to meet this mandated objective could impose requirements for more stringent cleaning or terminal bioload-reduction procedures comparable to that employed by the Viking missions. In extreme cases, satisfying planetary protection requirements might require spacecraft redesign or cancellation of an entire mission.

Using samples of the copper-oxide compound Sr2CuO3, the researchers lifted some of the electrons belonging to the copper atoms out of their orbits and placed them into higher orbits by manipulating them with X-rays. Upon placing them in these higher–and higher-velocity–orbits, the electrons split into two parts, one called a spinon that carried the electron’s spin with it, and another called an obitron that carried the electron’s orbital momentum with it.

Spin and orbit are–at least as our basic understanding goes–attached to each particular electron. So the fact that they have been separated is pretty significant. And while researchers have thought for a while that this kind of separation could be theoretically achieved, they’ve had a hard time proving it empirically until now. It’s a reminder that at the quantum level there are still things that more or less mystify us.
But that’s not all it is. This particular observation of an electron splitting could have big-time implications in the field of high-temperature superconductivity. Understanding the way electrons can decay into quasi-particles could improve our overall understanding of the electron and how it moves, and thus help us figure out new ways of moving electrons–or electricity–around in bulk without losing large amounts of it as waste.

The crabs in question, soldier crabs, live in large groups in lagoon environments (not to be confused with Shanghai hairy crabs, which live in a vending machine). When they move they swarm, with no real discernible leader. Crabs near the edges of the group exhibit serious leadership qualities, keeping the group together and moving in a direction as a cohesive body. Crabs in the interior of the group go with the flow, following their neighbors who are following their neighbors who are following the leaders at the edges.

But, interestingly, the soldier crabs also rotate regularly. Leader crabs at the edges cycle back into the interior, and interior crabs rotate to the outside, into leadership roles. All this happens without discussion of course. The direction and speed the crabs travel is often dictated by outside stimuli, such as the shadow of a crab-eating bird being cast on the group. But they more or less move as a unit, regardless of which crabs are in charge at any particular time.

When two swarms of crabs meet in motion, they tend to compromise by merging and continuing on in a direction that is the sum of the two swarms’ velocities, and this is where the computing comes in. The researchers built a system of channels in an environment that funnel the crabs along, like electrons flowing through a computer (they are prodded along by a fake bird shadow that is cast from overhead). Using a group of 40 real soldier crabs, the researchers tried to cajole the group into acting like a logic gate.

They found they could build a very reliable OR logic gate–where one or two swarms are merged into a single path. Creating the AND gate–one that requires the crabs to all swarm down one of three paths–was more difficult, but the researchers think they can improve its rate of success by altering the environment to be more friendly to the crabs.

All that means that, technically, you could build a classical computer using the presence or absence of a swarm of crabs to represent 1s and 0s. Which doesn’t impact you at all, since it would be kind of silly to actually build a working computer that works in such a way. But isn’t it cool that you could?

In February, there were  a study involving Japanese women whose reproductive stem cells were donated because they were undergoing gender reassignment surgery. Researchers at Massachusetts General Hospital were able tocoax these ovarian stem cells into becoming immature human egg cells, which were then incubated in mice so they’d have the proper ovarian structures. Now these same scientists, working with a team at Edinburgh University, want to fertilize them.

After sperm implantation, the scientists would watch the blastocysts develop into embryos for two weeks — the legal limit — and determine if they’re viable. Then these embryos would either be frozen or "allowed to perish," according to the independent. The tests would validate the stem-cell-derived human eggs, more properly called oocytes, and serve as an early indicator of whether they could someday be used to eradicate infertility.

Stem-cell derived oocytes could replenish the stocks of women undergoing menopause, or they could be used to allow infertile women to reproduce. The Independent goes so far as to mention an “elixir of youth,” wherein women of any age are full of stem-cell derived oocytes, remaining fertile and youthfully healthy forever.

This potential stem cell-based embryo construction still faces some hurdles — reproductive biologists are applying for a license to the Human Fertilisation and Embryology Authority in the UK. But if it’s approved, the eggs could be fertilized this year, according to the Independent.

Stem cells hold such great promise because they can differentiate into any cell, potentially replacing neurons, islet cells, kidney cells and more. But this research conceivably turns stem cells into an infinite supply of cellular material. The stem cell eggs would obviously most likely be used to help women conceive a child, but it’s not a huge leap to much more frightening scenarios: Stem cells turned into human egg cells, which could be fertilized to grow embryos, which would contain more stem cells, which could in turn be harvested …. and so on, as self-contained stem cell factories. It will be interesting to see how the UK authority interprets the possibilities.

Assistant professor Kee-Hong Kim from Purdue University is testing a compound that is commonly found in red wine for its ability to block the processes of fat cell development

Piceatannol results from the conversion of resveratrol – a compound found in red wine, grapes and peanuts that is also thought to combat cancer, heart disease and neurodegenerative diseases. When resveratrol is converted into the piceatannol compound, which naturally occurs after consumption, the compound has the ability to delay fat cell growth.

"Piceatannol actually alters the timing of gene expressions, gene functions and insulin action during adipogenesis, the process in which early stage fat cells become mature fat cells," explains Kee-Hong Kim, an assistant professor of food science at the Purdue University. "In the presence of piceatannol, you can see delay or complete inhibition of adipogenesis."

Young fat cells develop over a period of 10 days or more and go through several stages of development before becoming mature fat cells. The researchers are currently testing the effects of the piceatannol compound during the early stages of fat cell development before mature fat cells occur. "These precursor cells, even though they have not accumulated lipids, have the potential to become fat cells," Kim said. "We consider that adipogenesis is an important molecular target to delay or prevent fat cell accumulation and, hopefully, body fat mass gain."

The research found that piceatannol binds to insulin receptors of immature fat cells in the first stage of adipogenesis, blocking insulin’s ability to control cell cycles and activate genes that carry out further stages of fat cell formation. In other words, piceatannol is able to block the immature fat cells from maturing and growing.

Professor Kim will now start testing the compound with an animal model of obesity and hopes to find a way to protect piceatannol from degrading in the bloodstream. "We need to work on improving the stability and solubility of piceatannol to create a biological effect," Kim said.

Kim explains the study in the video below.

Knowing that stimulating various regions of the brain can trigger behaviors and memories, the researchers set out to manipulate specific memories by inserting two genes into mice. One of the genes produces receptors that the researchers could chemically trigger to activate a neuron. This gene was tied to a natural gene that turns on only in active neurons, such as those involved in the formation or recall of a particular memory. Put simply, the researchers installed on-off switches on neurons involved in the formation of specific memories.

The team’s main experiment saw the “on” switch triggered in neurons that were active as mice learned about a new environment – dubbed Box A – that had distinct colors, smells and textures. The mice were then given a chemical that would activate the neurons associated with the memories formed of Box A and placed in a second distinct environment – Box B.

When the chemical switch was turned on while they were in Box B, the mice showed signs of recognition, indicating that they were forming a kind of hybrid memory that combined their external observations (Box B) with their internal thoughts (Box A). Neither being in Box B without the chemical switch activated nor activating the switch outside of Box B produced memory recall by the mice.

“We know from studies in both animals and humans that memories are not formed in isolation but are built up over years incorporating previously learned information,” said Scripps Research neuroscientist Mark Mayford, who led the study. “This study suggests that one way the brain performs this feat is to use the activity pattern of nerve cells from old memories and merge this with the activity produced during a new learning session.”

The team is now working towards more precise control that will allow them to turn a specific memory on or off at will, so that a mouse will perceive itself to be in Box A, when it is in fact in Box B.

It is hoped that, once the processes are better understood, the research could lead to the development of drugs that target the perception process to help with the treatment of certain mental illnesses in which the patient’s brains produce false perceptions or disabling fears, such as schizophrenia and post traumatic stress disorder (PTSD). With drug treatments that target the neurons involved when a patient thinks about a certain fear, they could turn off the neurons involved and interfere with the disruptive thought patterns.

A Warp Field, According to the Alcubierre Drive

The Alcubierre warp drive–proposed by a Mexican physicist of the same name back in the 1990s–is a theoretical mechanism by which a spacecraft could deform the space-time continuum in a bubble around itself so it could travel faster than the speed of light while still staying within the parameters of special relativity. So a couple of honors students and their professor at the U. of Sydney School of Physics decided to take the Alcubierre warp drive for a theoretical spin. Their findings: there’s no soft landing at the other end of warp speed.

It turns out that bending the space-time continuum has its hazards. During faster-than-light travel, particles that come in contact with this Alcubierre bubble get trapped and accumulate in front it. Some particles can even enter the warp bubble. There is an aggregating effect here, the physicists found, so the longer the bubble travels, the more particles accumulate in front of it.

When the spacecraft is finally decelerated at its destination, that energy is released all at once with such high energy that virtually anything they come in contact with would be instantly destroyed. The particles that wormed their way inside the bubble could also threaten the spacecraft itself. This could be handy if your cruiser drops out of warp speed in the midst of an asteroid field, but it also means that if you dropped out of warp too close to your destination planet you could inadvertently wipe it off the interstellar map. Don’t tell The Galactic Empire.