February 07, 2007

From the "I Think I Know Something About This" Department

Storing light here -- and retrieving it there
7 February 2007
Nature 445 605

Physicists in the US have been able to imprint a coherent pulse of light on a collection of ultracold atoms -- and then retrieve the same light pulse from a second set of atoms that is some distance away. The experiment proves that macroscopic particles can be quantum mechanically indistinguishable even though they are physically separate. The work was carried out using Bose-Einstein condensates (BECs) -- atoms cooled to such low temperatures that they are all in the same quantum state.

Messenger atoms

To make light "jump" from one place to another, Lene Hau and colleagues from Harvard University exploited a technique that they developed in 2001 to store a light pulse in a BEC, which effectively slows laser light to a standstill. This technique involves shining a pulse from a probe laser onto a BEC of sodium atoms, which induces tiny oscillating distributions of electric charge in the atoms.

Normally these dipoles radiate and quickly decay, but shining a control laser onto the atoms transfers the oscillations in charge to oscillations in spin, which are more stable. So when the control laser is turned off, the information content of the probe pulse is "imprinted" on the oscillating spin dipoles of the atoms. Switching the control laser back on releases the light by allowing the atoms to reradiate coherently i.e. with the same phase of the original probe pulse.

What is different in the new experiment is that the delayed pulse is made to reappear from a second BEC situated some 160 ┬Ám away. The trick lies in the fact that the quantum-mechanical wave function of the spin dipoles is actually a superposition of atoms in the ground state and atoms in a spin-excited state. Because of conversation of momentum, the spin-excited atoms move away from the BEC when the atoms absorb photons from the pulse laser, while the ground-state atoms stay in the condensate.

The clever part of the experiment is that the Harvard team decided to wait until the spin-excited atoms had reached the second condensate before turning the control laser back on. To their delight, they found that that this physically separate collection of atoms was then able to re-emit the initial light pulse. This revived light pulse slowly propagated out of the second BEC before reaching its normal speed of 300 million metres per second.

Because the two BECs had been independently prepared, one might expect the "messenger wavepacket" transferred from the first condensate to be alien to the second BEC. The fact that it was not implies that the ground-state wavefunction has a component in both BECs at the same time, which can then combine with the spin-excited component once it had reached the second BEC. The experiment is a striking demonstration of quantum indistinguishability.

"By manipulating the matter copy [of the original light pulse], we can process optical information", says Hau. She told Physics Web that the experiment could lead to techniques to process optical information in optical communications and quantum-information networks. Other applications could be in ultra-sensitive rotation sensors or gravity detectors.

About the author: Jon Cartwright is a reporter for Physics Web.

Hat Tip: PhysicsWeb
Hat Tip: Nature

February 05, 2007

Transportation Security Officer Saves 10 People Asleep in Burning Building

A fire was engulfing the top floor of a three-story apartment house when TSO Catherine Burns spotted it as she drove to work at Hanscom Field Airport in Bedford, Mass. on the morning of January 17.
She immediately stopped and, realizing the fire was raging above residents as they slept, ran into the smoke-filled building.

"I just ran," said Burns. "I never did shut my car off. I just ran into the building."

Risking her own safety, Burns knocked on apartment doors on all three floors to wake sleeping residents who had not reacted to a faint smoke alarm. "The smoke wasn't that bad on the first floor," Burns recalled. "Once I knew I couldn't take it anymore and I thought everyone was out, I ran out, too."

Burns' heroic act is credited with saving the lives of all 10 people in the building – and a resident's dog.

The two-alarm fire rendered the building uninhabitable. Residents said they are grateful that "Good Samaritan" Catherine Burns was in the right place and the right time, willing to take action. She suffered minor smoke inhalation, but continued on to work at the airport.

"We are very proud of Catherine and the actions she instinctively took to help others in distress. She is an important part of our team and demonstrates that same type of commitment and dedication to her job in the airport every day," said FSD George Naccara. "Considering what she did on her way to work, then spent a full shift in the airport, on duty, as if this was just any other typical day for her - that is truly remarkable."

Hat Tip: TSA.Gov

February 03, 2007

The Day the Music Died

On this day in 1959, rising American rock stars Buddy Holly, Ritchie Valens and J.P. "The Big Bopper" Richardson are killed when their chartered Beechcraft
Bonanza plane crashes in Iowa a few minutes after takeoff from Mason City on a flight headed for Moorehead, Minnesota. Investigators blamed the crash on bad weather and pilot error. Holly and his band, the Crickets, had just scored a No. 1 hit with "That'll Be the Day."

After mechanical difficulties with the tour bus, Holly had chartered a plane for his band to fly between stops on the Winter Dance Party Tour. However, Richardson, who had the flu, convinced Holly's band member Waylon Jennings to give up his seat, and Ritchie Valens won a coin toss for another seat on the plane.

Buddy Holly, born Charles Holley in Lubbock, Texas, and just 22 when he died, began singing country music with high
school friends before switching to rock and roll after opening for various performers, including Elvis Presley. By the mid-1950s, Holly and his band had a regular radio show and toured internationally, playing hits like "Peggy Sue," "Oh, Boy!," "Maybe Baby" and
"Early in the Morning." Holly wrote all his own songs, many of which were released after his death and influenced such artists as Bob Dylan and Paul McCartney.

Another crash victim, J.P. "The Big Bopper" Richardson, 28, started out as a disk jockey in Texas. Jiles Perry Richardson was born October 24, 1930 in Sabine Pass, Texas.The family moved to Port Arthur when Jiles was still very young.After high school, Jiles decided to attend Lamar State College in Beaumont,Texas. While attending Lamar, Jiles found a job as a disc jockey and singer on the local radio station KTRM. Jiles coined his ownstage name, "The Big Bopper," while working at the station.

On April 18, 1952, The Big Bopper married Adrian Joy Fryon. Together, they would have one daughter which they named Deborah. In the May of 1957, Jiles established a world record for continuous broadcasting by working six straight days and spinning 1,821 records. During his tenure at KTRM, Jiles decided to write a few songs. Before long, he was discovered by Harold "Pappy" Daily. In 1957, Jiles released his most popular work, "Chantilly Lace," which became the third most played song of 1958. Jiles was overwhelmed with tour offers and decided to take them.

His last tour, the Winter Dance Party of 1959, was scheduled to play in remote locations throughout the midwest United States.The tour headlined with the likes of Buddy Holly, Ritchie Valens, and The Big Bopper (Jiles). The three musicians and their bands toured in a run down bus with a poor heating system. Because of these terrible circumstances, Jiles became ill with the flu. When the tour rolled into Clear Lake, Iowa, Buddy Holly chartered a plane to fly him and his band to the next tour stop after the show. When the show ended, Jiles approached Buddy's bassist, Waylon Jennings, and asked for Jennings' seat on the plane so that Jiles could get some rest and have time to schedule a doctors appointment. Waylon agreed and gave his seat to Jiles.

The third crash victim was Ritchie Valens, born on 13 May, 1941 in Pacoima, a suburb of Los Angeles, California. His real name was Richard Valenzuela. At nine years of age he got his first (Spanish) guitar. As a twelve year old Ritchie had already written several songs, most of which were inspired by Mexican music. He also displayed considerable singing talent, and became a feature at school assemblies singing and playing the guitar. When Ritchie was seventeen he was spotted by Bob Keene, president of Del Fi Records in Hollywood, and offered recording contract. Bob Keene also became his manager. His first single, the self-penned tune 'Come On Let's Go', sold 750,000 copies and earned him quite a reputation among teenagers all over the country.

Shortly after this, he wrote a song for his high school sweetheart, Donna Ludwig. The song 'Donna' was recorded and rapidly made the 1958 hit charts. It became his biggest all-time hit and first million seller it was a two-sided hit and the flip side 'La Bamba' was a traditional Spanish wedding song which Ritchie sang in Spanish after adding a rock'n'roll beat to it. That song was also a million seller.
Valens was posthumously inducted into the Rock and Roll Hall of Fame in 2001.

Singer Don McLean memorialized Holly, Valens and
Richardson in the 1972 No. 1 hit "American Pie," which
refers to February 3, 1959 as "the day the music

February 01, 2007

Tallest Buildings Timeline

World or Pulitzer Building
New York City (1889-90)

The History of Skyscrapers: A race to the top
by Karen Barss

The desire to build big is nothing new. Big buildings have been used to show off power and wealth; to honor leaders or religious beliefs; to stretch the limits of what's possible; and even as simple competition among owners, families, architects, and builders...

Taipei 101, Taipei, Taiwan;
(the Taipei Financial Center)
101 stories
and reaching
1,671 ft (509 m) high
world's tallest building (2003)

Hat Tip: InfoPlease.com

The History of Black History

Americans have recognized black history annually since 1926, first as "Negro History Week" and later as "Black History Month" [each February]

Hat Tip: Thompson - Gale
Windows Live Local / Virtual Earth

From the website of Keystone Aerial, one of the flyers using the Ultracam D. It's a page of images opportunistically snapped while contract flying. This shot of Mt. Rushmore is fabulous - they couldn't have had more dramatic lighting if they were directing the show

Hat tip: Resource Shelf