Quarter Electrons May Enable Exotic Quantum Computer

QUARTER ELECTRONS crop up in new experiments that create currents of electronlike "quasiparticles" (yellow). By forcing the current through a small junction (left to right), researchers deduced that the quasiparticles had one quarter the charge of single electrons—possibly the type needed for an exotic form of quantum computer.
Genia Brodsky, Weizmann Institute of Science

A pair of new studies documents the existence of "quasiparticles" with one quarter the electric charge of a single electron—odd, considering that electrons can not actually be split into smaller particles. More than a mere curiosity, the demonstration may hold the key to a powerful form of quantum computing in which the quasiparticles' quantum states could be braided together.

Fractional charges are nothing new. Researchers learned to make them more than 20 years ago by first confining electrons to a thin layer of semiconductor, chilling them to near absolute zero (–459.67 degrees Fahrenheit, or –273.15 degrees Celsius) and applying a magnetic field. They then introduced a voltage to initiate a current that flowed around the edges of the semiconductor sample, where it encountered resistance from the material.

Strangely, the resistance grew in steps that were too small to be explained by the motions of individual electrons. Researchers believe that the fractional quantum Hall effect, as it is known, occurs because electrons merge with portions of a magnetic field into collectives that flow like individual electrons. These discoveries garnered the 1998 Nobel Prize in Physics.

The fractional quantum Hall effect seemed destined to remain an abstruse playground until 2003, when researchers discovered that certain quasiparticles could lead to a highly stable topological quantum computer. Any kind of quantum computation derives its power from turning particles into quantum bits, which represent 0 and 1 simultaneously. In conventional approaches, researchers link quantum bits using wires or lasers, which risks exposing the bits to outside vibrations that would degrade their quantum character. In contrast, certain quasiparticles could connect simply by swapping locations, much like shuffling a deck of cards. The quasiparticles would "remember" the paths they took, no matter how intertwined, which (in theory) would make them more immune to noise.

"The ideas are beautiful, and they drive very beautiful science," says experimental physicist Moty Heiblum of the Weizmann Institute of Science in Rehovot, Israel. Past examples of quasiparticles all had odd fractional charges, such as one third. For quantum computing, pairs of quasiparticles would have to join up and generate quarter charges. Inspired by the theoretical work, Heiblum's group and a team from Harvard University and the Massachusetts Institute of Technology (MIT) separately set up fractional charge experiments as usual in a layer of aluminum gallium arsenide sandwiched between layers of gallium arsenide. But they tuned the middle layer to contain five electrons for every two magnetic field lines—the state predicted to generate quarter electron charges.

The Weizmann scientists measured random fluctuations in the current across a pinch in the plane, which allows only one charge-carrying particle through at a time. This "shot noise," similar to the static in a radio signal, was consistent with quasiparticles carrying one quarter an electron charge, the group reports in Nature. The second team obtained similar results, published in Science, by measuring current directly.

Not all quarter-charge particles would work for topological quantum computation. In physics-speak, they must also obey something called non-Abelian (non-commutative) statistics, which hinges on the strength of the interaction between the paired quasiparticles. The method used by the Harvard–MIT experimenters allowed them to measure that strength. It was not conclusive, but "the favored models do indeed have non-Abelian statistics," says Harvard physicist Charles Marcus.

The observation of the new quasiparticles is "quite neat and potentially seminal," says theoretical physicist Sankar Das Sarma of the University of Maryland, College Park. The definitive test of non-Abelian statistics will come, he says, when researchers learn to isolate pairs of quasiparticles side by side and swap their positions. The Weizmann and Harvard–MIT groups are working on that, but it may take a couple of years. Heiblum predicts that of all the experiments he has done, "it will be one of the most difficult."

Gold Accessories Cuffs

Gold Accessories Cuffs

Gold hasn't been so popular since James Bond and Goldfinger hit the cinema screens 40 years ago!

Gold colour and shimmering metallic gold has been featured in every autumn 2006 fashion collection. The simplest way to add gold colour to your wardrobe is with golden jewellery or with a metallic gold tone fashion accessory. There are plenty of affordable gold fashion items around such as necklaces bangles, bags and shoes.

You may already have something in your jewellery box at home like this vintage YSL costume jewellery metallic gold cuff, shown left from Elaine Mintzer's real vintage website at Lost Horizon Vintage.

Or a modern cuff like this Calow Stretch uneven edge bracelet gold cuff from John Lewis might be just the C21^st finishing touch you need.

If price is a problem, look no further than high street retailer Accessorize where later this autumn 2006, you can easily buy this simple gold tone bangle at Accessorize. Either a gold cuff or gold bangle would be good choice of golden accessory for this winter's look. The sixties feel of this gold bangle is very much in keeping with many of the modernist styles that you see in the shops.

Gold Fashion Jewellery

A gold tone chain necklace along the lines of this Calow piece from the John Lewis fashion jewellery range would make a useful gold accessory. It would give a lift to any dull workday. Equally this lovely necklace would adorn your evening outfit if you get invited unexpectedly for after work drinks.

So keep a jazz it all up necklace like this gold Calow & pearl multi chain necklace in your handbag and let fashion jewellery transform your image from day to evening.

At just £25 it won't break the bank and you can leave it in your bag all day without the real worry you might experience if it were expensive estate jewellery.

Boho necklaces have also maintained their popularity as a fashion accessory.

Gold Bags

For a luxury golden fashion look you could select this lovely shimmering Makki Collection bag called Suki from The Bag Boutique.

The handbag is beautifully crafted and features a band of smocking. It's a great evening bag.

The Bag Boutique is an online retail website dedicated to providing their customers with stylish, contemporary handbags from a range of UK designers.

If a whole garment in an opulent fabric seems too overpowering to you, look instead for a bag in gold brocade.

This large roomy golden brocade bag left is from sparklingaccessories.com and so is the smaller gold sequin disc evening bag below.

Or if you can afford it the Chloe Silverado like this metallic golden version below right is still going strong.

Gold Shoes

Of course the simplest way of all to become a golden lady is to add a pair of gold shoes. This autumn 2006 one of the most useful and fashionable of shoes will be the ballerina pump. Ballerina flats in all metallics including silver grey tones and animal prints are a fashion trend that is still gaining momentum.

Pretty Ballerina Flat Pump Shoes

You will find inexpensive gold ballet pumps in every high street shop selling shoes. What a practical, but great look. Ballerina flats along with newer styles of bootie shoes seem especially modern this fall. Team either type of footwear with fancy lace tights or leggings for the look of now.

With thicker tights or knee socks ballerinas can be used effectively to create the layered look. They will take you into autumn whilst your boots languish in the cupboard until a cooler day. What could be prettier than walking through autumnal leaves in your gold ballerinas.

But if you cannot get a pair easily consider ordering online from the website www.prettyballerinas.com which is based in Menorca. They have a very good selection of cute ballerina shoes in a variety of colours, styles and patterns.

You may like me even have your gold ballet flats already. These golden fashion ballerina shoes shown here are all images courtesy of www.prettyballerinas.com.

The pair called Audrey directly below are very attractive and doubly fashionable with their reptilian skin.

This pair of pretty gold ballerinas called Beatrice are in gold patterned leather. They are interesting in that they give the illusion of being flats, but have inner elevation.

Finally this ballerina shoe combines the current fascination for animal prints with a gold trim binding. But you can see some more of these ballerina shoes on other pages here soon.

Remember versions of gold ballet pumps will carry you into next year as they are perfect with fuller skirts.

Gold Evening Shoes

These spindly gold evening shoes below, won't break the bank and are standard stiletto heels that always have a place in the wardrobe. These gold shoes are from Matalan, are inexpensive at £14, cheap enough to wear for just one special evening. They cover the spectrum from true gold to copper gold. You could call them your Matalans!

However, if Manolos are your preference for gold shoes, then you will of course have an heirloom item, but also you need the funds to pay the price.

Primrose Wrap Cardigan

A small garment like this French Connection primrose yellow wrap cardigan at £65 may be an alternative answer to a simple gold accessory. But for a wardrobe in gold see the many gorgeous gold toned dresses, jackets and coats shown on my Gold Clothes Page.

French Connection image courtesy of John Lewis.

More fashion shoes are on the shoe and boots trend pages. See main new fashion trend looks and wardrobe tips. You can read more about fall 2006/7 handbags on the accessories page and about jewellery on the jewellery page.

Rare blue diamond breaks world record in HK sale

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HONG KONG (Reuters) - One of the rarest gems in the world, a flawless blue diamond, has sold for US$7.98 million (3.91 million pounds) at a Sotheby's auction in Hong Kong, making it the most expensive gemstone in the world, per carat, sold at auction.

After intense bidding, the 6.04 carat, internally flawless blue diamond fetched $HK61.9 million (3.91 million pounds), or US$1.32 million per carat. The price smashed a 20-year-old record held by the "Hancock Red" -- a red diamond, which fetched US$926,000 per carat at the time, Sotheby's said.

Sotheby's said the buyer was "Moussaieff Jewellers" in London which has a reputation for acquiring extremely rare and costly gemstones. The seller was a private Asian collector.

Blue diamonds have long captivated the rich and powerful -- shimmering with a certain dark mystique. The famous "Hope Diamond", a 45.52 carat grey-blue beauty, was passed down through the ages by King Louis XIV of France, Marie Antoinette and American heiress Evalyn Walsh McClean among others. It now rests in the Smithsonian Institute in Washington D.C.

The Sultan of Brunei reportedly bought another massive "blue" which surfaced briefly in the 1980s.

While not a large stone, the Sotheby's diamond has an esteemed cut and "fancy vivid blue" hue, factors which contributed to its blockbuster price -- roughly 10 times the per-carat price of regular white diamonds.

The blue hue is a result of trace amounts of boron in the stone's crystal structure.

Other coloured diamonds with pink and red hues can be mined in multiple locations across the globe including Brazil, India and Australia, but "blues" are mostly found at just one site on earth -- the Premier Mine in South Africa.

The Hope Diamond

The history of the stone which was eventually named the Hope diamond began when the French merchant traveller, Jean Baptiste Tavernier, purchased a 112 3/16-carat diamond. This diamond, which was most likely from the Kollur mine in Golconda, India, was somewhat triangular in shape and crudely cut. Its color was described by Tavernier as a "beautiful violet."

Tavernier sold the diamond to King Louis XIV of France in 1668 with 14 other large diamonds and several smaller ones. In 1673 the stone was recut by Sieur Pitau, the court jeweler, resulting in a 67 1/8-carat stone. In the royal inventories, its color was described as an intense steely-blue and the stone became known as the "Blue Diamond of the Crown," or the "French Blue." It was set in gold and suspended on a neck ribbon which the king wore on ceremonial occasions.

King Louis XV, in 1749, had the stone reset by court jeweler Andre Jacquemin, in a piece of ceremonial jewelry for the Order of the Golden Fleece (Toison D'Or). In 1791, after an attempt by Louis XVI and Marie Antoinette to flee France, the jewels of the French Royal Treasury were turned over to the government. During a week-long looting of the crown jewels in September of 1792, the French Blue diamond was stolen.

In 1812 a deep blue diamond described by John Francillion as weighing 177 grains (4 grains = 1 carat) was documented as being in the possession of London diamond merchant, Daniel Eliason. Strong evidence indicates that the stone was the recut French Blue and the same stone known today as the HopeDiamond. Several references suggest that it was acquired by King George IV of England. At his death, in 1830, the king's debts were so enormous that the blue diamond was likely sold through private channels.

The first reference to the diamond's next owner is found in the 1839 entry of the gem collection catalog of the well-known Henry Philip Hope, the man from whom the diamond takes its name. Unfortunately, the catalog does not reveal where or from whom Hope acquired the diamond or how much he paid for it.

Following the death of Henry Philip Hope in 1839, and after much litigation, the diamond passed to his nephew Henry Thomas Hope and ultimately to the nephew's grandson Lord Francis Hope. In 1901 Lord Francis Hope obtained permission from the Court of Chancery and his sisters to sell the stone to help pay off his debts. It was sold to a London dealer who quickly sold it to Joseph Frankels and Sons of New York City, who retained the stone in New York until they, in turn, needed cash. The diamond was next sold to Selim Habib who put it up for auction in Paris in 1909. It did not sell at the auction but was sold soon after to C.H. Rosenau and then resold to Pierre Cartier that same year.

In 1910 the Hope diamond was shown to Mrs. Evalyn Walsh McLean, of Washington D.C., at Cartier's in Paris, but she did not like the setting. Cartier had the diamond reset and took it to the U.S. where he left it with Mrs. McLean for a weekend. This strategy was successful. The sale was made in 1911 with the diamond mounted as a headpiece on a three-tiered circlet of large white diamonds. Sometime later it became the pendant on a diamond necklace as we know it today. Mrs. McLean's flamboyant ownership of the stone lasted until her death in 1947.

Harry Winston Inc. of New York City purchased Mrs. McLean's entire jewelry collection, including the Hope diamond, from her estate in 1949. This collection also included the 94.8-carat Star of the East diamond, the 15-carat Star of the South diamond, a 9-carat green diamond, and a 31-carat diamond which is now called the McLean diamond.

For the next 10 years the Hope diamond was shown at many exhibits and charitable events world wide by Harry Winston Inc., including as the central attraction of their Court of Jewels exhibition. On November 10, 1958, they donated the Hope diamond to the Smithsonian Institution, and almost immediately the great blue stone became its premier attraction.

The Hope diamond has left the Smithsonian only four times since it was donated. In 1962 it was exhibited for a month at the Louvre in Paris, France, as part of an exhibit entitled Ten Centuries of French Jewelry. In 1965 the Hope diamond traveled to South Africa where it was exhibited at the Rand Easter Show in Johannesburg. In 1984 the diamond was lent to Harry Winston Inc., in New York, as part of the firm's 50th anniversary celebration. In 1996 the Hope diamond was again sent to Harry Winston Inc., in New York, this time for cleaning and some minor restoration work.

The weight of the Hope diamond for many years was reported to be 44.5 carats. In 1974 it was removed from its setting and found actually to weigh 45.52 carats. It is classified as a type IIb diamond, which are semiconductive and usually phosphoresce. The Hope diamond phosphoresces a strong red color, which will last for several seconds after exposure to short wave ultra-violet light. The diamond's blue coloration is attributed to trace amounts of boron in the stone.

In the pendant surrounding the Hope diamond are 16 white diamonds, both pear-shapes and cushion cuts. A bail is soldered to the pendant where Mrs. McLean would often attach other diamonds including the McLean diamond and the Star of the East. The necklace chain contains 45 white diamonds.

Mrs. Evalyn Walsh McLean wearing the Hope Diamond with the McLean Diamond (31.26 Carats) and Star of the East (94.8 Carats) attached

In December of 1988, a team from the Gemological Institute of America visited the Smithsonian to grade the great blue stone using present day techniques. They observed that the gem shows evidence of wear, has a remarkably strong phosphorescence, and that its clarity is slightly affected by a whitish graining which is common to blue diamonds. They described the color as a fancy dark grayish-blue. An examination on the same day by another gemologist using a very sensitive colorimeter revealed that there is a very slight violet component to the deep blue color which is imperceptible to the naked eye. Still, one can only wonder that the original 112 3/16-carat stone bought by Tavernier was described as "un beau violet" (a beautiful violet).

The World of Rare Stones: Painite is the World's Rarest Gem

The world's rarest gem is believed to be painite, a gem that most have never even heard of. Rarity does not equate to beauty in gems, however. The painite is an orangish or reddish brown, with the brown tint coming from iron in the crystal. It was first discovered in Burma in the 1950s and was widely considered to be the rarest of all gems, with only two faceted crystals in existence. Within the last couple of years, however, the source of the original painite crystals was discovered, and now a few hundred faceted stones exist.

A more widely recognized (but still very rare) gem is the red diamond. There are many more red diamonds available than some other rare gems, but very large red diamonds are extremely rare. The largest cut natural red diamond may be the one owned by Moussaieff Jewellers Ltd, a 5.11 carat trillion cut.

The rare blue diamond, made famous by the Hope Diamond, gets its deep blue color from traces of boron in the stone. It is a natural blue diamond, in contrast with most of today's blue diamonds, which are turned from clear to blue with a process involving irradiation and heat.

The Hope Diamond was believed to be originally over 112 carats, but was poorly cut. It was recut in the 1600's, resulting in a stone just over 67 carats. It changed hands many times, and got its name from Henry Philip Hope, who acquired the diamond in 1839. After it changed hands a few more times, the Hope Diamond came to rest in the care of the Smithsonian, and now weighs over 45 carats.