Subscribe free to our newsletters via your
. 24/7 Space News .




TIME AND SPACE
Tricking the Uncertainty Principle
by Jessica Stoller-Conrad
Pasadena CA (SPX) May 20, 2014


The tiny aluminum device-only 40 microns long and 100 nanometers thick-in which Caltech researchers observed the quantum noise from microwaves. Image courtesy Chan Lei and Keith Schwab/Caltech.

Today, we are capable of measuring the position of an object with unprecedented accuracy, but quantum physics and the Heisenberg uncertainty principle place fundamental limits on our ability to measure. Noise that arises as a result of the quantum nature of the fields used to make those measurements imposes what is called the "standard quantum limit."

This same limit influences both the ultrasensitive measurements in nanoscale devices and the kilometer-scale gravitational wave detector at LIGO. Because of this troublesome background noise, we can never know an object's exact location, but a recent study provides a solution for rerouting some of that noise away from the measurement.

The findings were published online in the May 15 issue of Science Express.

"If you want to know where something is, you have to scatter something off of it," explains Professor of Applied Physics Keith Schwab, who led the study.

"For example, if you shine light at an object, the photons that scatter off provide information about the object. But the photons don't all hit and scatter at the same time, and the random pattern of scattering creates quantum fluctuations"-that is, noise. "If you shine more light, you have increased sensitivity, but you also have more noise. Here we were looking for a way to beat the uncertainty principle-to increase sensitivity but not noise."

Schwab and his colleagues began by developing a way to actually detect the noise produced during the scattering of microwaves-electromagnetic radiation that has a wavelength longer than that of visible light. To do this, they delivered microwaves of a specific frequency to a superconducting electronic circuit, or resonator, that vibrates at 5 gigahertz-or 5 billion times per second. The electronic circuit was then coupled to a mechanical device formed of two metal plates that vibrate at around 4 megahertz-or 4 million times per second.

The researchers observed that the quantum noise of the microwave field, due to the impact of individual photons, made the mechanical device shake randomly with an amplitude of 10-15 meters, about the diameter of a proton.

"Our mechanical device is a tiny square of aluminum-only 40 microns long, or about the diameter of a hair. We think of quantum mechanics as a good description for the behaviors of atoms and electrons and protons and all of that, but normally you don't think of these sorts of quantum effects manifesting themselves on somewhat macroscopic objects," Schwab says. "This is a physical manifestation of the uncertainty principle, seen in single photons impacting a somewhat macroscopic thing."

Once the researchers had a reliable mechanism for detecting the forces generated by the quantum fluctuations of microwaves on a macroscopic object, they could modify their electronic resonator, mechanical device, and mathematical approach to exclude the noise of the position and motion of the vibrating metal plates from their measurement.

The experiment shows that a) the noise is present and can be picked up by a detector, and b) it can be pushed to someplace that won't affect the measurement. "It's a way of tricking the uncertainty principle so that you can dial up the sensitivity of a detector without increasing the noise," Schwab says.

Although this experiment is mostly a fundamental exploration of the quantum nature of microwaves in mechanical devices, Schwab says that this line of research could one day lead to the observation of quantum mechanical effects in much larger mechanical structures. And that, he notes, could allow the demonstration of strange quantum mechanical properties like superposition and entanglement in large objects-for example, allowing a macroscopic object to exist in two places at once.

"Subatomic particles act in quantum ways-they have a wave-like nature-and so can atoms, and so can whole molecules since they're collections of atoms," Schwab says. "So the question then is: Can you make bigger and bigger objects behave in these weird wave-like ways? Why not? Right now we're just trying to figure out where the boundary of quantum physics is, but you never know.

"This work was published in an article titled "Mechanically Detecting and Avoiding the Quantum Fluctuations of a Microwave Field."

Other Caltech coauthors include senior researcher Junho Suh; graduate students Aaron J. Weinstein, Chan U. Lei, and Emma E. Wollman; and Steven K. Steinke, visitor in applied physics and materials science. The work was funded by the Institute for Quantum Information and Matter, the Defense Advanced Research Projects Agency, and the National Science Foundation.

The device was fabricated in Caltech's Kavli Nanoscience Institute, of which Schwab is a codirector.

.


Related Links
The Gravitational Wave Detector at LIGO
Understanding Time and Space






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle








TIME AND SPACE
Radiation from Early Universe Key To Major Questions In Physics
San Diego CA (SPX) May 15, 2014
Astrophysicists at UC San Diego have measured the minute gravitational distortions in polarized radiation from the early universe and discovered that these ancient microwaves can provide an important cosmological test of Einstein's theory of general relativity. These measurements have the potential to narrow down the estimates for the mass of ghostly subatomic particles known as neutrinos. ... read more


TIME AND SPACE
LRO View of Earth

Saturn in opposition tonight, will appear next to the moon

Russia to begin Moon colonization in 2030

Astrobotic Partners With NASA To Develop Robotic Lunar Landing Capability

TIME AND SPACE
When fantasy becomes reality: first seeds to be planted soon on Mars

NASA Rover Gains Martian Vista From Ridgeline

Opportunity Explores Region of Aluminum Clay Minerals

NASA's Saucer-Shaped Craft Preps for Flight Test

TIME AND SPACE
Airbus design of European service module for Orion approved by ESA

Swiss Space Systems launch the ZeroG experience

Britain's Longitude Prize back after 300-year absence

Sea level rise forces US space agency to retreat

TIME AND SPACE
Moon rover Yutu comes closer to public

The Phantom Tiangong

New satellite launch center to conduct joint drill

China issues first assessment on space activities

TIME AND SPACE
New ISS Expedition Unaffected by Proton Crash

US-Russian Tensions Roiling Outer Space Cooperation

Scientists Seek Answers With Space Station Thyroid Cancer Study

Rounding up the BCATs on the ISS

TIME AND SPACE
SpaceX's Dragon spacecraft returns to Earth from space station

Third-stage engine glitch causes Proton-M accident

Russia's Roscosmos plans to launch two more Protons this year

SpaceX Dragon Spacecraft Returns Critical NASA Science from ISS

TIME AND SPACE
Starshade Could Help Photograph Distant Planets

Giant telescope tackles orbit and size of exoplanet

Odd planet, so far from its star

New Exomoon Hunting Technique Could Find Solar System-like Moons

TIME AND SPACE
MIPT Experts Reveal the Secret of Radiation Vulnerability

Pentagon plans multi-billion dollar project to combat space junk

Russian space agency to create equipment for monitoring space debris

Electrons hurtle into the interior of a new class of quantum materials




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.