Physicists move closer to the quantum limit - GoFuckYourself.com

Juicy D. Links · 04-06-2004, 11:20 PM

A new experiment in the US has come close to detecting quantum effects in a macroscopic object. Keith Schwab and colleagues from the National Security Agency (NSA) working at the University of Maryland have measured the vibrations of a tiny nanoelectromechanical arm to probe the limits at which quantum behaviour breaks down and classical physics takes over. Although the experiment was not quite sensitive enough to test the uncertainty principle, it has come closer to doing so than previous attempts (M D LaHaye et al. 2004 Science 304 74).

The uncertainty principle states that we cannot simultaneously know both the position and velocity of a particle with complete certainty. The principle is used to describe the motion of particles at the atomic level, but has thus far not been observed in the behaviour of macroscopic objects. Such behaviour is described by classical physics.

To find out whether or not the uncertainty principle extends up to the macroscopic world, Schwab and colleagues studied the motion of a vibrating mechanical arm made from silicon nitride. At just 8 microns (8x10-6m) long, the arm is tiny by everyday standards but still macroscopic (having the mass equivalent to 1012 hydrogen atoms).

The researchers positioned the arm about 600 nanometres away from a single-electron transistor - which acts as a motion detector - and coupled the two together via a capacitor. They then applied a voltage to make the arm vibrate and cooled the system down to a few millikelvin. Cooling the system to such low temperatures reduced thermal vibrations close to the point where just "zero-point" quantum fluctuations remain. This zero-point motion results from the uncertainty principle, which prevents the arm from remaining completely at rest.

As the arm moved towards the detector, and then away from it, the amount of current flowing through the transistor changed. By measuring this current, the physicists were able to measure the displacement of the arm with a sensitivity that is only about a factor of 4.3 larger than the amplitude of zero-point fluctuations.

The NSA physicists now plan to increase the sensitivity of the detector and further reduce thermal vibrations in the arm. They also hope to extend their study to larger objects. "These experiments address a deep mystery in physics: where does the quantum world stop and the classical world begin?" Schwab told PhysicsWeb. "Success at manipulating the quantum state of a mechanical device would suggest that there is no boundary and encourage us to pursue even larger objects."

Schwab says his team would like to exploit the system for quantum computing applications.

modelgigtalent · 04-06-2004, 11:21 PM

Illicit · 04-06-2004, 11:22 PM

wow ! you dont say...

Juicy D. Links · 04-06-2004, 11:22 PM

Quote:

Originally posted by modelgigtalent

baaaa baaaaa

Juicy D. Links · 04-06-2004, 11:23 PM

Quote:

Originally posted by ajpiii
wow ! you dont say...

Elli · 04-06-2004, 11:26 PM

Do you have a link?

Juicy D. Links · 04-06-2004, 11:33 PM

Quote:

Originally posted by Elli
Do you have a link?

http://physicsweb.org/article/news/8/4/1

Check out the archives some interesting stuff

Giorgio_Xo · 04-06-2004, 11:33 PM

Tax dollars well spent. That shit is awesome.

foreverjason · 04-06-2004, 11:34 PM

the future is upon us.

spentrent · 04-06-2004, 11:43 PM

<i>Where Does the Weirdness Go?</i> by David Lindley is a great layman's guide to quantum mechanics.

pimplink · 04-07-2004, 01:04 AM

nice stuff but can it help us or it's just some kind
of their discoveries?

spentrent · 04-07-2004, 01:07 AM

Quote:

Originally posted by pimplink
nice stuff but can it help us or it's just some kind
of their discoveries?

All scientific research helps us. There's no such thing as "pragmatic research."

StuartD · 04-07-2004, 01:08 AM

Quote:

Originally posted by pimplink
nice stuff but can it help us or it's just some kind
of their discoveries?

Didn't you ever see Quantum Leap? That guy saved people all the time, so it's gotta be good.

Wilber · 04-07-2004, 01:11 AM

Quantum mechanics broke down in super string theory. That's old news.

Greg B · 04-07-2004, 01:29 AM

Quote:

Originally posted by juicylinks

http://physicsweb.org/article/news/8/4/1

Check out the archives some interesting stuff

reynold · 04-07-2004, 02:57 AM

Another cool breakthrough!

spentrent · 04-07-2004, 03:00 AM

Quote:

Originally posted by Wilber
Quantum mechanics broke down in super string theory. That's old news.

I wish I was one of the 3 guys who understands string theory.

mijoon · 04-07-2004, 04:43 AM

Quote:

Originally posted by juicylinks

A new experiment in the US has come close to detecting quantum effects in a macroscopic object. Keith Schwab and colleagues from the National Security Agency (NSA) working at the University of Maryland have measured the vibrations of a tiny nanoelectromechanical arm to probe the limits at which quantum behaviour breaks down and classical physics takes over. Although the experiment was not quite sensitive enough to test the uncertainty principle, it has come closer to doing so than previous attempts (M D LaHaye et al. 2004 Science 304 74).

The uncertainty principle states that we cannot simultaneously know both the position and velocity of a particle with complete certainty. The principle is used to describe the motion of particles at the atomic level, but has thus far not been observed in the behaviour of macroscopic objects. Such behaviour is described by classical physics.

To find out whether or not the uncertainty principle extends up to the macroscopic world, Schwab and colleagues studied the motion of a vibrating mechanical arm made from silicon nitride. At just 8 microns (8x10-6m) long, the arm is tiny by everyday standards but still macroscopic (having the mass equivalent to 1012 hydrogen atoms).

The researchers positioned the arm about 600 nanometres away from a single-electron transistor - which acts as a motion detector - and coupled the two together via a capacitor. They then applied a voltage to make the arm vibrate and cooled the system down to a few millikelvin. Cooling the system to such low temperatures reduced thermal vibrations close to the point where just "zero-point" quantum fluctuations remain. This zero-point motion results from the uncertainty principle, which prevents the arm from remaining completely at rest.

As the arm moved towards the detector, and then away from it, the amount of current flowing through the transistor changed. By measuring this current, the physicists were able to measure the displacement of the arm with a sensitivity that is only about a factor of 4.3 larger than the amplitude of zero-point fluctuations.

The NSA physicists now plan to increase the sensitivity of the detector and further reduce thermal vibrations in the arm. They also hope to extend their study to larger objects. "These experiments address a deep mystery in physics: where does the quantum world stop and the classical world begin?" Schwab told PhysicsWeb. "Success at manipulating the quantum state of a mechanical device would suggest that there is no boundary and encourage us to pursue even larger objects."

Schwab says his team would like to exploit the system for quantum computing applications.

I decohere , therefore I am .

04-06-2004, 11:20 PM	#1
Juicy D. Links So Fucking Banned Industry Role: Join Date: Apr 2001 Location: N.Y. -Long Island -- Posts: 122,992	Physicists move closer to the quantum limit A new experiment in the US has come close to detecting quantum effects in a macroscopic object. Keith Schwab and colleagues from the National Security Agency (NSA) working at the University of Maryland have measured the vibrations of a tiny nanoelectromechanical arm to probe the limits at which quantum behaviour breaks down and classical physics takes over. Although the experiment was not quite sensitive enough to test the uncertainty principle, it has come closer to doing so than previous attempts (M D LaHaye et al. 2004 Science 304 74). The uncertainty principle states that we cannot simultaneously know both the position and velocity of a particle with complete certainty. The principle is used to describe the motion of particles at the atomic level, but has thus far not been observed in the behaviour of macroscopic objects. Such behaviour is described by classical physics. To find out whether or not the uncertainty principle extends up to the macroscopic world, Schwab and colleagues studied the motion of a vibrating mechanical arm made from silicon nitride. At just 8 microns (8x10-6m) long, the arm is tiny by everyday standards but still macroscopic (having the mass equivalent to 1012 hydrogen atoms). The researchers positioned the arm about 600 nanometres away from a single-electron transistor - which acts as a motion detector - and coupled the two together via a capacitor. They then applied a voltage to make the arm vibrate and cooled the system down to a few millikelvin. Cooling the system to such low temperatures reduced thermal vibrations close to the point where just "zero-point" quantum fluctuations remain. This zero-point motion results from the uncertainty principle, which prevents the arm from remaining completely at rest. As the arm moved towards the detector, and then away from it, the amount of current flowing through the transistor changed. By measuring this current, the physicists were able to measure the displacement of the arm with a sensitivity that is only about a factor of 4.3 larger than the amplitude of zero-point fluctuations. The NSA physicists now plan to increase the sensitivity of the detector and further reduce thermal vibrations in the arm. They also hope to extend their study to larger objects. "These experiments address a deep mystery in physics: where does the quantum world stop and the classical world begin?" Schwab told PhysicsWeb. "Success at manipulating the quantum state of a mechanical device would suggest that there is no boundary and encourage us to pursue even larger objects." Schwab says his team would like to exploit the system for quantum computing applications.

04-06-2004, 11:21 PM	#2
modelgigtalent Confirmed User Join Date: May 2003 Location: Sin Sity - Hit me here! ICQ: 165829688 Posts: 2,208	__________________ Web marketing - video editing - color correcting and more. ICQ -165829688

04-06-2004, 11:22 PM	#3
Illicit wtf ? Join Date: Dec 2003 Location: GFY Posts: 11,895	wow ! you dont say... __________________ Insert Sig Here

04-06-2004, 11:26 PM	#6
Elli Reach for those stars! Industry Role: Join Date: Apr 2003 Location: Vancouver, BC Posts: 17,991	Do you have a link? __________________ email: [email protected]

04-06-2004, 11:33 PM	#8
Giorgio_Xo Confirmed User Join Date: Mar 2003 Location: Las Vegas, NV Posts: 4,263	Tax dollars well spent. That shit is awesome. __________________ Make Levees, Not War

04-06-2004, 11:34 PM	#9
foreverjason Confirmed User Join Date: Mar 2003 Posts: 1,452	the future is upon us.

04-06-2004, 11:43 PM	#10
spentrent Confirmed User Join Date: Feb 2004 Location: LA Posts: 876	<i>Where Does the Weirdness Go?</i> by David Lindley is a great layman's guide to quantum mechanics.

04-07-2004, 01:04 AM	#11
pimplink Confirmed User Join Date: Jun 2001 Location: Closer than you think Posts: 9,535	nice stuff but can it help us or it's just some kind of their discoveries? __________________ Need Mainstream Content and SEO? SEO * Website Copy * Blogs Blogging - PR Work - Forum Marketing - Social Marketing - Link building - Articles 100% Guaranteed Content!

04-07-2004, 01:11 AM	#14
Wilber Confirmed User Join Date: May 2001 Location: De,Oh,Lei Posts: 1,295	Quantum mechanics broke down in super string theory. That's old news. __________________ Sig NOT for sale

04-07-2004, 02:57 AM	#16
reynold Too lazy to set a custom title Join Date: Oct 2002 Location: Global Traveler Posts: 51,271	Another cool breakthrough!