Cosmic to Quantum

scienceisbeauty:

Experimental set-up of the quantum teleportation device including an entangled light-emitting diode (ELED) and an assortment of beam splitters polarization controllers, detectors, and photodiodes.

Source: Quantum teleportation performed with light from a quantum dot embedded in an LED, Phys.Org

NIST’s Quantum Simulator Mimics Hundreds of Qubits Interacting

In a case that’s somewhat chicken-and-egg, one of the many reasons computer scientists and physicists are pursuing a working quantum computer is to model quantum systems themselves. Modeling some quantum properties for systems even with a just a few dozen particles is impossible on even the biggest conventional supercomputers, and the pursuit of new materials and next-level science requires that we find a way to do so. So it’s notable that physicists at the National Institute of Standards and Technology (NIST) have constructed a quantum simulator can simulate interaction between hundreds of quantum bits.

This isn’t the holy grail of quantum computing by any means, but it’s an exciting step forward. The NIST simulator is basically a single layer of beryllium ions, hundreds of them stretching across a circular plane less than one millimeter in diameter hovering inside a chamber known as a Penning trap. The quantum bit—or qubit—in this case is the outermost electron of each ion, which acts as the quantum equivalent of the classical bit, the 0 or 1 (or both at the same time, in quantum context).

By cooling the ions to near absolute zero with a laser and then hammering them with carefully timed microwave and laser pulses, the NIST physicists are able to get the electrons to interact in controlled ways that mimic—at least mathematically—complex quantum systems that can’t be studied practically in the laboratory. Thus, it’s more a quantum system simulator than a true quantum computer, but it’s exciting nonetheless. This kind of sim could help physicists model and study extremely complex and amazing theoretical materials, like high-temperature superconductors that could someday move electricity across vast distances in power grids without losing much of it as heat.

The early benchmarking experiments look good for this quantum sim, the NIST reports, though in order to benchmark their creation experiments had to be carried out with relatively weak interactions between electrons since the system had to be simple enough to be confirmed by a classical computer. Here, the physicists bumped up against one of the key problems facing the field of quantum computing.

To check the efficacy of the first quantum computers (or simulators) scientists will need a working quantum computer—a paradox that is going to lead to some fits and starts along the way to building a true quantum computing platform. Early quantum breakthroughs are going to produce the equivalent of algebra problems for which it’s impossible to work backwards to check the accuracy of the answer. But hey, this is the bleeding edge of quantum physics and computer science—and certainty is boring anyhow.

Clay Dillow, PopSci

blindmen6:

                                         Quark Flavors and Colors

Quarks are described as coming in six different flavors, but each quark has an anti-quark, so there are also six different anti-flavors. The six quark flavors are named up, down, strange, charm, bottom and top;the six anti-flavors, anti-up, anti-down, anti-strange, anti-charm, anti-bottom and anti-top.

Protons are viewed as being constructed of two up-quarks and one down-quark. Up-quarks have an electric charge of +^2e/₃ and down-quarks have an electric charge of -^e/₃. Adding these charges up, we get a net charge of +1e for a proton. Neutrons are viewed as being constructed of two down-quarks and one up-quark, in which the electric charges add up to 0 (zero).

Each of the six flavors of quarks can have three different colors: red, blue and yellow. There are, of course, also anti-colors: anti-red, anti-blue and anti-yellow. The quark forces (strong force) bind quarks together only in colorless combinations of three quarks (baryons), quark-antiquark pairs (mesons) and possibly larger combinations such as the pentaquark that could also meet the colorless requirement.

Quarks undergo transformations by the exchange of W bosons. These transformations determine the rate and nature of the decay of hadrons by the weak interaction (radioactive decay).

mathphysics:

crownedrose:

Composer Makes Music From Positron Trails in Cloud Chambers

Music composer and network engineer Domenico Vicinanza has brought together his two loves by making music from the particle tracks of positrons passing through cloud chambers.

The sealed metallic vessels are filled with superheated liquids or vapors, which detect electrically charged particles passing through them, like the more modern silicon particle detectors used in the LHC at Cern. Positrons fired through the chambers — antiparticles of electrons, a trillionth of a meter in size — are subatomic and make no measurable sound by themselves, so Vicinanza had to work out a method to bring their music to life.

He took data stored on the International Science Grid that depicts the tracks, or routes, taken through the chambers by positrons, and draws those directly onto music staves. The elegant arcs and lines are then used as a path over which music notes are laid. Vicinanza composes the melodies himself and his customized software automatically harmonizes the tracks.

“My plan is to sonify some of the early tracks recorded with cloud chambers. I was thinking of a piano trio,” Vicinanza told iSGTW. The resulting music (.mp3) sounds a little like scales being played simultaneously — one ascending in notes and the other descending.

“Displays of these events are perfectly symmetric tracks spiraling in opposite directions. Their sonification will be two symmetric melodies, moving in opposite directions,” said Vicinanza, a network engineer at Dante (Delivery of Advanced Network Technology to Europe), Cambridge.

It’s not the first time the engineer has merged art with science. Previous works include music written using data from volcanic seismograms performed by the City Dance Ensemble, and 2,000-year-old Greek music re-created by his troupe, the Lost Sounds Orchestra.

2012 marks 101 years since the invention of Wilson cloud chambers by Charles Thomas Rees Wilson, a Scottish physicist. This year is also the 60th anniversary of the invention of the bubble chamber, by American physicist Donald Glaser, and the first observation of the positron.

Brilliant, really. Is it sad I thought of degenerate perturbation theory when I saw that first image?

quantumaniac:

Quantum Gravity

Within the current understanding of physics, we have many large problems. One of these is that we have two major theories that describe the four fundamental forces -quantum mechanics (QM) and general relativity (GR). QM describes three of the four known fundamental forces, and GR describes gravity. However, all attempts thus far to develop a single theory out of these have been for naught - but the pursuit is known as quantum gravity. 

Development of a theory of quantum gravity would hope to unify all four fundamental forces into a single mathematical framework, which would naturally describe all known observable interactions in the universe - from the subatomic to cosmological scale. Both of the current major theories, QM and GR, work well when applied to their own scales - but fail miserably when, for example, quantum physics is applied to macroscopic scales. 

Many researchers and scientists believe that the eventual discovery of a theory of quantum gravity will deal with symmetry - as much of the universe works around symmetrical laws. However, this does not always happen, symmetry is broken in, for example, CP violation. 

A theory of quantum gravity could also be known as the Theory of Everything (TOE). One of the most notable and common ones is String Theory, which basically surmises that, at its tiniest scales, the universe’s matter is composed of tiny, vibrating strings. The frequencies at which these strings vibrate correspond to the particle’s individual properties.  

quantumaniac:

Feynman Diagrams

The interactions of subatomic particles can be challenging to understand - and even more-so to express mathematically. Although the mathematics that these diagrams represent is highly complex - the events are usually fairly simple. Typically, these diagrams are most useful in QED (Quantum Electrodynamics) and QCD (Quantum Chromodynamics.) 

For example, in this diagram - an electron, shown as e^-, and a positron, shown as e⁺, collide. Since a positron is the antimatter equivalent of an electron, upon collision the two particles annihilate one another - creating a photon, described by the blue wiggly line. The photon eventually produces a quark, anti-quark pair - one of which releases a gluon (shown by the green line.) 

Feynman diagrams are remarkable for their way of bringing these complex equations down to an easily comprehendible level - they allow physicists to take a step away from the pages of equations to take a look at what is really happening. 

The position and representation of the axes are up to personal preference, the two dimensions of time and space can be on either the x or y-axis - whichever is more easily comprehendible by the particular scientist. 

Plus, drawing a few of these little buggers on random papers makes you look super-smart. 

Petite Particle Accelerator: A Proton Gun For Killing Tumors

Since 1990, doctors have been regularly treating cancer patients using proton beams, which work similarly to radiation. Proton therapy is more precise, however, causing less harm to healthy surrounding tissues. Unfortunately, generating a proton beam requires a particle-accelerator facility that’s the size of an airplane hangar and costs more than $100 million to build. Thus, proton-beam therapy remains a rarity, with only 37 working facilities worldwide, 10 of which are located in the U.S. Just 10,000 people were treated last year, less than 5 percent of suitable patients.

Now scientists at the Compact Particle Acceleration Corporation in Livermore, California, are developing a 13-foot-long particle accelerator that costs about $30 million. Most accelerators use large magnets to generate the electromagnetic field that pushes charged particles. The magnets require 10-foot-thick concrete shielding and bulky hardware. CPAC’s prototype creates the electromagnetic field with electric lines, which don’t require massive shielding or large additional equipment. The new accelerator could be commercially available as soon as 2015. (The numbers below will match you up to the location in the picture above.)

1. PROTON BEAM Magnets in the kicker pull positively charged protons from hydrogen plasma made by a duoplasmatron. A deflecting magnet collects the stream into proton bundles, which then enter the injector, where a microwave field speeds the particles toward the acceleration chamber at up to five million mph.

2. LASER At nearly the same time, a laser fires a light pulse, which splits into fiber-optic cables of various lengths.

3. ACCELERATION CHAMBER As a bundle of protons enters the acceleration chamber, a light pulse hits the chamber’s first pair of electric lines, triggering the release of electrons. The resulting electromagnetic field propels the proton bundle forward. The light pulse triggers the electric lines in a wave, sequentially accelerating the proton bundle until it’s traveling at 335 million mph—or about half the speed of light.

4. CLOCK The entire process is controlled by a clock, which directs magnets to turn on or off and the laser to fire.

5. ROBOTIC CHAIR Moving a patient is easier than moving a 13-foot-long particle accelerator. A robotic chair maneuvers a strapped-in patient in front of the proton beam to target a tumor from different angles.

Spencer Woodman