Beam Me Up Scotty? Quantum Teleportation

Beam Me Up Scotty? Quantum Teleportation

Why the effect is nothing like Star Trek

 
TELEPORTATION may inspire images of instant travel, but physicists today see it more as a component of quantum computers.

The sci-fi dream (or utter fantasy) of getting from one place to another instantaneously continued this February 14, with the opening of Doug Liman's film Jumper, based on the novel by Steven Gould. We asked quantum physicist H. Jeff Kimble of the California Institute of Technology to explain how physicists understand quantum teleportation, which turns out to be more relevant to computing than to commuting. 

What's the biggest misconception about teleportation?
That the object itself is being sent. We're not sending around material stuff. If I wanted to send you a Boeing 757, I could send you all the parts, or I could send you a blueprint showing all the parts, and it's much easier to send a blueprint. Teleportation is a protocol about how to send a quantum state—a wave function—from one place to another.

Is transmitting a quantum state hard to do?
The most straightforward way to do it would be to imagine it was an electron: just shoot the electron from point A to point B and it takes its quantum state with it. But that’s not always so good, because the state gets messed up in the process.

How does teleportation get around the disruption of the quantum state?
The special resource that enables teleportation is entanglement. You're Alice [in location A], and I hand you an electron in an unknown quantum state. Your job is to send the quantum state (not the electron) to location B, which is Bob. If you try to measure it directly, you necessarily disturb it.

You and Bob also share a pair of electron—you have one, Bob has the other—and they're in an entangled state such that if yours is spinning up, his is spinning down and conversely.

You make a joint measurement of two electrons—the one I handed you and the one you're sharing with Bob. And that gives you two bits of information. You call up Bob on the cell phone and give him those two bits, and he uses them to manipulate his electron. And bingo, in the ideal case he can perfectly re-create the state of the electron that I handed you.

Why doesn't Alice just copy the quantum state and store the copy?
There are uncertainty relations like Heisenberg's uncertainty principle. When I hand my electron to Alice, what she might think to do is just keep a copy—clone it. The more information she tries to get about the state, the less good is the teleportation. If she tries to keep a perfect copy, then Bob would create a state that is perfectly random.

Why would you want to transmit a quantum state? What are the applications?
Imagine you want to build a quantum computer. A quantum computer is going to have parts just like a computer on your desktop. They have to be wired together quantum mechanically. The quantum memory's got to talk to the quantum processor. Teleportation is just a fancy quantum wire.

Why not just shoot electrons around?
If I carry this electron from the memory to the processor and I make a mistake—say it collides with some impurity in the wire—then I've lost more than just the state of that one electron. That one spin is entangled, potentially, with all the spins in the computer.

How has the field advanced since the first demonstrations of quantum teleportation in 1997?
All the initial work was done with light. In 1998 my team demonstrated teleportation of a beam of light. I would say that was the first bona fide demonstration. A beam of light came in, and a beam of light came out. In the experiments your magazine covered, there was never a moment you could say, aha, the state has emerged and been teleported.

A few years ago [in 2004] a group led by David J. Wineland at the National Institute of Standards and Technology in Boulder, Colo.—and simultaneously with that, a group led by Rainer Blatt in Innsbruck, Austria—teleported the internal spin of a trapped ion. It’s the first time teleportation had been done with the state of a massive particle. The quantum state of one ion was teleported to a second ion using a third ion in the middle as an intermediate.

More recently [in 2006], the group of Eugene S. Polzik at the University of Copenhagen teleported the quantum state of light directly into a material system. All the other experiments had been teleportation from an atom or a photon to exactly the same kind of particle.

Do these demonstrations have any practical value?
It has practical implications, because a quantum computer is going to be a hybrid system. Light is good for propagating from one place to the other with very low loss, but it's really hard to store light. Some quantum information protocols require you to take light and map it into some material system, where you can store it for a long time. Then if you want to communicate across your computer or across the country, you map it back into light.

I should tell you one other experiment. A scientist named TK Furusawa at the University of Tokyo teleported entanglement. He had one beam of light that was entangled to a second beam; he teleported the first beam and he could show it was still entangled with the partner that wasn't teleported.

How would keeping a teleported object entangled with its unteleported partner be useful?
The quantum computer's working on thousands of entangled spins and from time to time I need to teleport the state of the 561st electron to another place. Well that's not as simple as just thinking it's that one electron.

Switching gears—this new movie, Jumper, is about a kid, and some other people, who teleport from place to place.
I didn't know that.

If you saw X-Men, with Nightcrawler…
I haven't seen X-Men either.

Do you watch Heroes on NBC?
No. I watch some of the football playoffs.

But you know Captain Kirk…
I have some advice. Just don't talk about teleporting people in your story. The technical base of our society is information commerce, and in the next 20 years it will radically change. Read the semiconductor industry's roadmap. We're just going to gleefully think it's going to happen on the movie screen, and we will ignore investments in science and technology.

There's a really incredibly exciting frontier in science that didn't exist 15 or 20 years ago, and it's this quantum information science, which brings together traditional computer science and quantum mechanics. There's stuff going on that is just titillating.

Europa Here We Come: NASA Tests Under-Ice Sub with Eye Toward Jupiter

Europa Here We Come: NASA Tests Under-Ice Sub with Eye Toward Jupiter

If successful at mapping lake terrain Wisconsin and Antarctica, it could be used to search for life in the ocean on Jupiter's moon

 
UNDER-ICE SUBMARINER: NASA's Environmentally Non-Disturbing Under-ice Robotic Antarctic Explorer (ENDURANCE) is designed to operate autonomously in frigid water.

 
ENDURANCE'S top shell resembles a crab, but its underbelly has a variety of sensors that measure temperature, light and water chemistry during its eight-hour missions.

 
FROZEN FRONTIER: ENDURANCE entered Wisconsin's Lake Mendota via a 10-foot (3.1 m) by 14-foot (4.3 m) rectangular dive hole cut using chainsaws.

 
ICY RECEPTION: Rather than diving right in (literally) ENDURANCE was initially suspended just below Lake Mendota's surface to see how its controls and its two lithium ion batteries would function in the cold.

 
DIVING IN: Prior to ENDURANCE's descent, a triangular hole was cut so a diver could check to see there were no ice formations that might damage the robotic sub.

Researchers from NASA and the University of Illinois at Chicago atop the frozen surface of Wisconsin's Lake Mendota this week are preparing for interplanetary exploration. Below them, under a sheet of ice more than a foot (30 centimeters) thick, the space agency's new Environmentally Non-Disturbing Under-Ice Robotic Antarctic Explorer (ENDURANCE) maps the lake's underwater terrain. If this and subsequent voyages are successful, a similar vessel could be sent to navigate the suspected liquid water under the frozen surface of the ocean on Jupiter's moon Europa by the year 2028.

ENDURANCE, a $2.3-million project funded by NASA's Astrobiology Science and Technology for Exploring Planets (ASTEP) program, is an autonomous vehicle designed to operate underwater below the ice. Its mission: to gather environmental data (such as samples of microbial life) and create three-dimensional maps of undersea topography.

The Lake Mendota effort is a practice run for a month-long mission it is set to undertake later this year in Antarctica's permanently frozen Lake Bonney, which is coated with up to 15 feet (4.5 meters) of ice. The lake, which is about 2.5 miles (four kilometers) long, one mile (1.6 kilometers) wide, 130 feet (40 meters) deep and located in the continent's McMurdo Dry Valleys, was chosen because its extreme conditions are about as close as it gets on Earth to those ENDURANCE might encounter on Europa. If this trip to Antarctica is successful, ENDURANCE will do a second mapping next year.

All data gathered from these expeditions will be sent to the University of Illinois's Electronic Visualization Laboratory, where researchers will create 3-D images, maps and data renderings of the lake. ENDURANCE begins mapping from the melt hole through which it enters the water. Using the GPS coordinates of the opening, the vehicle's positions are determined data gleaned from sensors that measure temperature, light and the water's chemistry. During its eight-hour missions, gathered information is stored on board using flash disk memory for later recovery and analysis on the surface.

Workers cut a 10-foot (3.1-meter) by 14-foot (4.3-meter) rectangular dive hole with a chainsaw to prepare an entry point for ENDURANCE in Lake Mendota's icy surface. Because ENDURANCE enters and leaves its underwater habitats via ice holes, it is designed to be a compact vehicle—about 4.7 feet (1.4 meters) long, 3.5 feet (1.1 meters) wide, and 2.6 feet (0.8 meter) high and weighing about 176 pounds (80 kilograms) on land. The propulsion chassis uses commercial components along with custom-designed flight electronics and thrust vector controllers. Maximum vehicle speed is anticipated to be as much as five feet (1.5 meters) per second.

Most of the onboard scientific instrumentation is fiber-optic-based and mounted along the wall of a flow-through tube that runs the entire interior length of the vehicle. Chloride and conductivity probes sense the same flow stream at the rear of the vehicle. A digital camera with lighting sits on the starboard bow (located on the right, if you are facing the sub's front) for capturing visible spectrum images within each volume pixel (voxel) as well as for taking bottom sediment images. Three-dimensional images are composed of voxels in the same way that two-dimensional ones are built from pixels.

ENDURANCE, which runs on two lithium ion batteries, detects and avoids obstacles using sonar arrays mounted on the bow, port (left) and starboard sides that can alert the vessel about an object up to 328 feet (100 meters) away. The sonar's detection range is expected to give ENDURANCE at least a minute before it reaches any obstacle.

An ultrashort baseline transceiver is lowered into the water once ENDURANCE submerges and emits signals that give the autonomous vessel a point of reference. This aids the vessel's mapping mission and also helps the researchers retrieve their robot sub. A malfunction that might cause ENDURANCE to get lost or be unable to make its way back to the entry hole would be disastrous due to the harsh conditions in which it operates. "When you put something in a lake in Antarctica, you don't want to lose it," says John Rummel, a NASA senior scientist for astrobiology.

ENDURANCE is a follow-up to the Deep Phreatic Thermal explorer (DEPTHX) , a NASA-funded project led by StoneAerospace, Inc., a Del Valle, Tex.based maker of technology used to explore the ocean depths as well as deep space. DEPTHX last year underwent extensive underwater field tests in Mexico, and its success has paved the way for ENDURANCE's missions.

Whereas the DEPTHX was tested in waters that were a balmy 86 degrees Fahrenheit (30 degrees Celsius), ENDURANCE will encounter 32-degree F (0-degree C) conditions in Lake Bonney, whose stratified waters contain both fresh- and salt- water. Nearest its surface, Bonney has a layer of about 16 feet (five meters) of freshwater atop about 110 feet (33.5 meters) of saltwater, the latter of which is three times as saline as normal seawater, Rummel says. This increased saltiness will cause ENDURANCE's sonar waves to behave differently, bouncing upward more than they would in fresh or less briny water.

NASA's otherworldly aspirations for ENDURANCE include a trip to Europa, which Rummel says the agency hopes to pull off within in two decades. ENDURANCE has to prove its mettle on Earth, however, before it is ready to dive under Europa's ocean, which features up to 12 miles (20 kilometers) of ice atop water that could be around 62 miles (100 kilometers) deep. Once there, ENDURANCE could play a very special role in space exploration, Rummel says, adding, "It could very well be the first vehicle to find extraterrestrial life."

Trash-Based Biofuels: From Landfill to Full Tank of Gas

Trash-Based Biofuels: From Landfill to Full Tank of Gas

Lawn clippings and unrecycled paper could help break the world's oil addiction

 
WASTE NOT, WANT NOT: By fermenting the cellulose in unrecycled paper or lawn clippings, enough ethanol to offset one third of U.S. fuel consumption can be made.

The remains of plants processed for human purposes molder in landfills across the world. Whether waste paper or raked leaves, the plant remnants still contain cellulose, a sugar in greenery that bonds with the chemical compound lignin to furnish a plant's structure. Microbes living in the landfills break down this cellulose into methane, which slowly seeps to the surface and into the atmosphere, where it is a potent greenhouse gas. BlueFire Ethanol, Inc., in Irvine, Calif., would rather harvest that energy for use as cellulosic ethanol fuel.

"We produce 70 gallons of ethanol per ton of waste," says engineer Arnold Klann, BlueFire's president and CEO. "The trick is unlocking the sugar molecule from the lignin, which is the glue that holds it together."

BlueFire estimates 40 billion gallons of cellulosic ethanol could be produced from plant waste destined for the landfill, providing as much as one third of all U.S. transportation fuel needs. And, if other forms of waste, such as the stalks of corn plants (corn stover) or the remnants of timber harvest are included, Klann says, "we have enough feedstock in the U.S. to offset 70 percent of the oil import."

BlueFire is set to open its first plant at a landfill in Lancaster, Calif., later this year and hopes to use U.S. Department of Energy (DOE) funding to open a second by the end of 2008, Klann says. Together the two plants would produce, at best, 22 million gallons of ethanol a year by using sulfuric acid to break the lignocellulose bonds and then burning the leftover lignin to power fermentation of the cellulose into ethanol. "The lignin we recover makes up 70 percent of the steam and electricity we need," Klann notes. "The other advantage of siting at a landfill is that they have methane gas. We can burn that in our boiler and generate huge carbon credits."

Given the potential benefits, Congress has provided $10 million in funding—and the DOE has asked for $30 million more—to develop a second facility employing the process, as well as millions more for similar cellulosic biorefineries, such as the Range Fuels plant in Soperton, Ga., that converts wood waste into fuel.

Biofuels from waste avoid the carbon and energy debts incurred by more common examples such as ethanol from corn or diesel from soy. "The thing we know will work is if you use waste products," says agricultural expert Tim Searchinger of Princeton University, who led recent research showing that most biofuels do little to slow and may even increase global warming. "If everything is done right, probably we can use corn stover without other problems, though it might mean you have to grow a cover crop."

Biofuels also offer one of the few methods currently available for storing solar energy, notes chemical engineer Charles Wyman of the University of California, Riverside. "Biomass to liquid fuel, electricity for charging of a battery or generating hydrogen, [those are] really our options," he says. "The best way to store solar energy is called biomass."

BlueFire has already operated such a plant to convert wood waste into ethanol in Japan to demonstrate the feasibility of the technology. As a result, the government of that country has decided to mandate blending 1 percent of ethanol into gasoline for the first time. And Klann believes this technology could prove most useful in the developing world, where plant waste is typically burned rather than buried. "What we have to do as a society is figure out how to move ourselves around in a way that is low-cost and has minimal effect on the environment," he says. "Ethanol is not a bad fuel."

Many States Elect Not to Use Flawed E-Voting Technology

Many States Elect Not to Use Flawed E-Voting Technology

Eight years after the controversial 2000 presidential election, electronic voting systems still fail to deliver on their promise of accuracy and security

 
NO CONFIDENCE VOTE: Nearly eight years after the contentious 2000 presidential election, electronic voting has yet to deliver on its promise of accurate, secure ballot tabulation, causing many states to revert back to paper ballots.

With just nine months to go until Election Day, electronic voting machines remain as iffy and controversial as ever. The new technology was once widely viewed as an improvement over the antiquated paper ballots used in some states during the highly contentious 2000 presidential race that ushered George W. Bush into the White House (think: hanging chads). But it is still plagued by accuracy and security concerns.

In a recent report, the Government Accountability Office (GAO)—Congress's investigative arm—gave at best a lukewarm endorsement of electronic voting technology. Congress called upon the GAO to investigate the role that iVotronic direct-recording electronic (DRE) touch-screen voting machines, made by Election Systems & Software, Inc., in Omaha, Neb., played in the highly controversial 2006 election for Florida's 13th Congressional District, in which Republican Vern Buchanan edged out Democrat Christine Jennings by a whisker-thin 369 vote margin.

During that election, more than 18,000 of the 143,532 ballots cast on the e-voting machines in Florida's Sarasota County did not register a vote for either candidate. The GAO checked for flaws in voting machines used during that election in Sarasota County. As part of the effort, investigators examined the firmware (software embedded in the devices) to make sure it matched that certified by the State of Florida. They also tested the devices to make sure they properly recorded and counted the ballots and whether they could provide accurate results even if miscalibrated.

The agency's conclusion: "Although the test results cannot be used to provide absolute assurance, we believe that these test results, combined with the other reviews that have been conducted by Florida, GAO, and others, have significantly reduced the possibility that the iVotronic DREs were the cause of the undervote."

Although hardly a ringing endorsement for e-voting technology, the GAO's findings contradicted those of researchers at Dartmouth College and the University of California, Los Angeles, who, after conducting a separate study (released in September) found that the "exceptionally high ... undervote rate" in the Florida's 13th District race "was almost certainly caused by" a poorly designed and confusing electronic ballot displayed on the voting machine's touch screen.

Florida's own assessment of its e-voting technology statewide has been even less enthusiastic. The state last May commissioned a review led by Florida State University's Security and Assurance in Information Technology (SAIT) laboratory of voting system software made by Diebold Election Systems (which now calls itself Premier Election Solutions). Two months later, investigators released a scathing report in which they describe a glitch in Diebold's optical-scan firmware that enabled a "type of vote manipulation if an adversary can introduce an unofficial memory card into an active terminal" prior to an election. Such a card can be preprogrammed to essentially swap the electronically tabulated votes of two candidates or reroute all of one candidate's votes to a different candidate. The investigators simulated a cyber strike on their test systems and had no trouble carrying it out despite new mechanisms designed to protect against "similarly documented attacks in previous studies," the report states.

SAIT also found that the systems' encryption algorithms "had some cryptographic flaws," says SAIT co-director Alec Yasinsac, a Florida State University associate professor of computer science. In particular, the keys required to lock and unlock encrypted information were difficult to manage and safeguard against potential hackers. Once they cracked the encryption code, investigators found, intruders were able to access all encrypted data in the voting machine. "The types of attacks are very real," he says.

One of the greatest challenges when securing computers is accounting for the unexpected, says Seth Hallem, CEO of Coverity, Inc., the San Francisco–based maker of the source code analysis software that SAIT used during its probe of Diebold's system. This is becoming more difficult as increasingly sophisticated software—including that which runs electronic voting machines—continues to grow to encyclopedic portions. One program can contain tens of millions of lines of code.

Whereas certain technology—such as pacemakers and other medical devices—are heavily regulated and must adhere to strict design and construction standards, voting machines are still mostly unregulated. "There's no validation of how the software for these systems is designed and built," Hallem says, adding that this is "surprising given the importance of voting machines to our national infrastructure."

This has caused problems throughout the U.S. as different states attempt to assess the effectiveness of their e-voting technology. Following a review of e-voting machine security vulnerabilities and source code, California Secretary of State Debra Bowen in August decertified all e-voting machines in her state, other than those designed for disabled voters. Ohio Secretary of State Jennifer Brunner recently released the results of a probe into her state's electronic voting systems that concluded they, too, were riddled with "critical security failures" that could impact the integrity of elections.

"In the year 2000, when the Florida election went nuts, there were some electronic systems, but by and large the vast majority was done on handwritten ballots and punch ballots," SAIT co-director Yasinsac says. In the wake of the controversy, e-voting was held up as a way to restore integrity to the process. "We pushed this technology even though it was not ready," he adds. "Much of the software that the machines used is more than 10 years old and has been revised heavily, making it harder to review."

Any significant changes in election technology will come too late for this year's bid for the White House. In states such as Maryland, where Democratic Governor Martin O'Malley has proposed spending $6.8 million to buy new optical-scan machines to improve the accuracy of that state's elections, the technology will not be ready to go until 2010. Meantime, legislation introduced to the U.S. House of Representatives last year by Representative Rush Holt [D-N.J.] that would require voter-verified permanent paper ballots (amending the tech-friendly but misguided Help America Vote Act of 2002) is languishing in committee and will not impact this year's elections.

City Pulse Captured for Real-Time Tripping

City Pulse Captured for Real-Time Tripping

City in Motion
A screen shot from a real-time dynamic map of Rome depicts the location of buses (yellow arrows) and the distribution of pedestrians (red cloud). A related project is underway for the cities of Lisbon and Porto. The dynamic system would process real-time traffic and crowds and factors like construction and immediately calculate the best way for a commuter to get around town.

Crowds. Traffic jams. Bus and train delays. Pollution. Life in the big city can sometimes bog you down.

Now for the first time, researchers are working on a dynamic, public transportation program that could improve your commute.

The CityMotion project, being coordinated through the MIT-Portugal Program, will capture a variety of real-time digital data already being produced or recorded for other reasons and re-purpose it to enhance mobility in Lisbon and Porto.

Such a system could help make planning the best route easier for a range of people from city officials to disaster evacuation planners to supply-chain managers to average commuters.

The first application will be a customized trip planner in which citizens can choose their journey based on the quickest, cheapest or most environmentally friendly path possible.

"Every few minutes, we get a big chunk of data that says, 'at this point in the city there are this many people.' It's a method of sensing the city," explained Assaf Biderman, assistant director of the SENSEable City Laboratory at the Massachusetts Institute of Technology in Cambridge.

Biderman and colleagues at MIT have teamed up with researchers at the University of Porto, the University of Coimbra and the Instituto Superior Tecnico as part of the program's three-year timeline.

To sense congestion information in the cities, Biderman and his colleagues will pull data from sensors already distributed throughout a city.

For example, highways already have roadside sensors that regularly record the passing of cars. Tollbooths are able to calculate the number of cars passing through, based on vehicles using radio frequency identification tags for automatic payments. Location information about bus, subways and trains is already captured by public transportation authorities to manage schedules.

And many cities already have a network of pollution sensors distributed throughout neighborhoods to monitor air quality.

Crowd information can also be gleaned from mobile phone use. Biderman and his colleagues from the SENSEable City Lab already initiated a separate project in Italy, called WikiCity Rome that produces an interactive map showing the location of people in real time based on anonymous and aggregated data collected from cell phones and GPS devices.

Processing the wide variety of sensed information involves customized algorithms that are able to strip the digital data down to its essential message (such as, "Is it the location of a bus?" or, "What is the amount of pollution on the north side of town?"). 

Once that information is discovered, it is plugged into computer models that can make predictions about traffic and crowd flow.

That way, when a user makes a query such as "what's the fastest route from A to B," the program can analyze the overall system to make the best prediction.

On one day, the fastest route might involve taking a bus because track maintenance is slowing down the subways. On another day, the fastest trip might be by foot, because a parade has closed down a main street used by the bus.

How the user gets the information has to do with the third and final layer: information dissemination.

"It will start on the Web, but ideally it could be on in-car navigation systems, mobile devices or interactive urban furniture," said Assaf

But before they get to that point, they'll have to overcome a couple of hurdles.

"I would find two big challenges. One is putting all of the data providers in agreement. The other big challenge is to make people interested in the system," said Carlos Lisboa Bento, professor of information engineering at the University of Coimbra in Portugal.

The team is working on moving toward agreements particularly with telecommunication and transportation partners. Getting the public interested will involve proving that there is a real advantage to the system.

"One important aspect is that she or he perceives that the system is safe in terms of privacy and security," said Bento.

At the end of three years, Biderman and his team hope to have those problems resolved.