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By linking the electrical currents of two superconductors large enough to be seen with the naked eye, researchers have extended the domain of observable quantum effects. Billions of flowing electrons in the superconductors can collectively exhibit a weird quantum property called entanglement, usually confined to the realm of tiny particles, scientists report in the Sept. 24 Nature.
“It’s an exciting piece of work,” comments physicist Steven Girvin of Yale University. “People are interested in pushing the boundaries of quantum mechanics.”
Entanglement is one of the strangest consequences of quantum mechanics. After interacting in a certain way, objects become mysteriously linked, or entangled, so that what happens to one seems to affect the fate of the other. For the most part, researchers have only found signs of entanglement between tiny particles, such as ions, atoms and photons.
John Martinis and colleagues at the University of California, Santa Barbara looked for entanglement between two superconductors, each less than a millimeter across. These superconducting circuits, made of aluminum, were separated by a few millimeters on an electronic chip. At low temperatures, electrons in the superconductors flow collectively, unfettered by resistance.
Despite each superconductor’s relatively large size, the electrons within move together in a naturally coherent way. “There are very few moving parts, so to speak,” Girvin says, which helped the scientists spot evidence of entanglement. “It’s a general fact that the larger an object is, the more classical it is in its behavior, and the more difficult it is to see quantum mechanical effects.”
In the new study, researchers used a microwave pulse to attempt to entangle the electrical currents of the two superconductors. If the currents were quantum-mechanically linked, one current would flow clockwise at the time of measurement (assigned a value of 0), while the other would flow counterclockwise when measured (assigned a value of 1), Martinis says. On the other hand, the currents’ directions would be completely independent of each other if everyday, classical physics were at work.
After attempting to entangle the superconducting circuits, Martinis and his team measured the directions of the currents 34.1 million times. When one current flowed clockwise (measured as a 0), the team found, the other flowed counterclockwise (measured as a 1) with very high probability. So the two were linked in a way that only quantum mechanics could explain.
“It has to be in this weird quantum state for you to get those particular probabilities that we measure,” Martinis says. “The percentages of those different things are not something that you can classically predict.”
Finding entanglement between superconductors is “a fairly important milestone,” comments Anthony Leggett of the University of Illinois at Urbana-Champaign. The new study “does seem to be rather unambiguous evidence for entanglement.”
Such entangled superconductors might be used as a component in a powerful quantum computer, Leggett says. “People are very interested in the possibility of building a quantum computer,” and these kinds of systems may be quite good for that, he says.
Martinis says that the technology for building advanced electrical circuits may be used to build quantum circuits, too. “The hope is that since we know how to put together integrated circuits in complex ways, that maybe we can make very complex quantum circuits in the same way,” he says.
He cautions, though, that a good quantum computer is a long way off. Researchers still need to find a way to make entangled superconducting circuits last longer. And a good quantum computer would need more than two circuits. Martinis says his group will try to entangle three and four such circuits next.
In addition to providing technological advances, the new results add to the debate over where to draw the line between quantum mechanics and the everyday physics that governs large-scale phenomena. Researchers want to know how far quantum weirdness can go.
“It’s interesting to test quantum mechanics on a large scale,” Girvin says. “Do things look classical on large scales because there’s something wrong with quantum mechanics? Personally, I think that’s wrong, but one never knows.”
Found in: Atom & Cosmos
- L. Sanders. "Mechanical systems all tangled up.
The motion of two ion pairs is linked through 'spooky action at a distance.'"
July 4th, 2009; Vol.176 #1 (p. 8)
[Go to] - D. Castelvecchi. "Welcome to the Quantum Internet:
Quantum encryption is here, but the laws of physics can do much more than protect privacy."
August 16th, 2008; Vol.174 #4
[Go to]
- Violation of Bell’s inequality in Josephson phase qubits
Markus Ansmann, H. Wang, Radoslaw C. Bialczak, Max Hofheinz, Erik Lucero, M. Neeley, A. D. O’Connell, D. Sank, M. Weides, J. Wenner, A. N. Cleland & John M. Martinis
Nature, Vol 461,24 September 2009
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"Researchers still need to find a way to make entangled superconducting circuits last longer." How long do they last?
That explains and afirms that the LHC can now afirm that a theory, the one of the Higg's boson, is a certainty, not a theory no more.
Despite of not been seen they can be observed.
Just like a mirror. One light, one piece of light, the photon, mirroring, that close, one another.
Do light think?
Or does "quantum-mechanically linked" imply that this is not possible...
One of these ideas centers around the production of very large numbers of individually entangled pairs of such sub-millimeter scale circuits or other systems wherein the total rest mass of the circuits would be on the order of say 2 million metric tons. One half of the set of entangled elements would be brought along as space craft fuel while the other half would be kept back in the solar system at a safe distance from Earth.
Now imagine if one or perhaps even a few of such sub-millimeter entangled objects could be placed in a rocket chamber or an energy extraction chamber in a precisely catalogued and timed predetermined manner while their conjugate partners back here in the solar system where blasted with a beam of electromagnetic energy, a charged particle beam, and/or the like, where in the total energy of the beam energy interacting with a given conjugate object was many many times, and perhaps even many orders of magnitude greater than the total rest mass energy density of each object of a given pair of sub-millimeters scale objects.
If the energy was departed quickly enough throughout the conjugate partner back here in the solar system so that the entangled state of both partners of a pair remained as the partner back in the solar system was ablissimated, perhaps the partner located within the rocket cone or energy extraction chamber within the ship would undergo an explosion wherein the energy of the explosion would be equal to that of the energized debris produced immediately upon the onset and termination of the beam/ conjugate partner interaction process that occurred back in our solar system.
Assuming that the interaction energy as such was an arbitrary multiple greater than unity of the total rest energy of a completely entangled conjugate partner located within the space craft energy extraction system and that the partner aboard the space craft would explode with the same energy as the interaction energy within the partner back in the solar system, and that the explosion at the location of the space craft was converted completely to space craft propulsion energy with 100 percent efficiency, the effective Isp of the conjugate objects aboard the space craft would be theoretically equal to mC expressed in units of C.
My reasoning behind this calculation is as follows. Since the fuel of a perfectly efficient matter antimatter rocket wherein both components of fuel are carried on board from the start of the mission in their entirely has a specific impulse expressed in units of C equal to 1C, and since the specific impulse of a fuel can be expressed as the amount of momentum delivered to the space craft per unit of fuel, for the case where only the antimatter fuel is carried onboard from the start of a mission wherein the matter component is extracted from the interstellar medium, in the case of 100 percent system efficiency, the effective momentum delivered to the space craft per unit of on board fuel is effectively doubled since the quantity of reaction mattergy is effectively doubled per unit of onboard rocket fuel. Thus, one would assume that the effective Isp of the carried on board from the beginning antimatter fuel would be equal to 2C.
Likewise, the effective Isp of a perfectly efficient entangled element based rocket fuel or energy source as described above would be equal to 2C where the interaction energy within the exploding element back in the solar system is equal to twice the total rest energy of the sub-millimeter element. Thus for cases where the energy of interaction as such is perfectly utilized aboard the space craft for cases where the interaction energy is an arbitrary large multiple, a of the element rest mass-energy, the specific impulse should be equal to aC and the energy released in the space craft chamber should be equal to a M[C EXP 2].
Taking the relativistic rocket equation, we have Delta V = C tanh{[Isp/C] ln (Mo/M1)} = C tanh{[a C/C] ln (Mo/M1)} = C tanh{(a) ln (Mo/M1)}.
Now let us assume that a = 100, and that M0/M1 = 1,000 and that thus the dry mass of the space craft = 1,000 metric tons whereas the fully fuel mass 1 million metric tons.
Therefore, Delta V = C Tanh{[100 C/C]ln(1,000)} = C Tanh[100 ln(1,000)] = C – e1 where e1 is miniscule.
This value of Delta V is extremely close to C.
Taking the relativistic rocket equation, and a more reasonable value for a we have Delta V = C Tanh{[Isp/C] ln (Mo/M1)} = C Tanh{[a C/C] ln (Mo/M1)} = C Tanh{(a) ln (Mo/M1)} = C Tanh{[10 C/C]ln(1,000)} = C Tanh[10 ln(1,000)] = C – e2 where e2 is miniscule.
Even this value of Delta V is extremely close to C.
Now let us assume that a = 100, and that M0/M1 = 2 and that thus the dry mass of the space craft = 1,000 metric tons whereas the fully fuel mass 2,000 metric tons. Therefore we have Delta V = C Tanh{[Isp/C] ln (Mo/M1)} = C Tanh{[a C/C] ln (Mo/M1)} = C Tanh{(a) ln (Mo/M1)} = C Tanh{[100 C/C]ln(2)} = C Tanh[100 ln(2)] = C – e3 where e3 is miniscule.
The resulting value of Delta V is extremely close to C, even with an Mo/M1 value of only 2 .
Note that the notations of C – e1, C – e2, and C – e3, denote subscripts of 1, 2, and 3 rather than multiplicative factors.
We now assume that a = 10, and that M0/M1 = 2 and that thus the dry mass of the space craft = 1,000 metric tons whereas the fully fueled mass = 2,000 metric tons. Therefore we have Delta V = C tanh{[Isp/C] ln (Mo/M1)} = C tanh{[a C/C] ln (Mo/M1)} = C tanh{(a) ln (Mo/M1)} = C tanh{[10 C/C]ln(2)} = C tanh[10 ln(2)] = 0.9999980926463 C. For this value of v, gamma = 1/{{1 – [(v/C) EXP 2]} EXP (1/2)} = 500.
Even this value for Delta V is close to C.
We now assume that a = 10, and that M0/M1 = 4 and that thus the dry mass of the space craft = 1,000 metric tons whereas the fully fueled mass 4,000 metric tons. Therefore we have Delta V = C tanh{[Isp/C] ln (Mo/M1)} = C tanh{[a C/C] ln (Mo/M1)} = C tanh{(a) ln (Mo/M1)} = C tanh{[10 C/C]ln(4)} = C tanh[10 ln(4)] = 0.99999999999818C. For this value of v, gamma = 1/{{1 – [(v/C) EXP 2]} EXP (1/2)} ~ 500,000
This value for Delta V is close to C.
We now assume that a = 10, and that M0/M1 = 5 and that thus the dry mass of the space craft = 1,000 metric tons whereas the fully fueled mass 5,000 metric tons. Therefore we have Delta V = C tanh{[Isp/C] ln (Mo/M1)} = C tanh{[a C/C] ln (Mo/M1)} = C tanh{(a) ln (Mo/M1)} = C tanh{[10 C/C]ln(5)} = C tanh[10 ln(5)] = 0.99999999999998. For this value of v, gamma = 1/{{1 – [(v/C) EXP 2]} EXP (1/2)} ~ 5,000,000.
This value of gamma for Delta V is much greater than the relativistic gamma factor that protons will obtain in the Large Hadron Collider when it resumes operation at its designed collision energy limits.
How extreme can we go with an M0/M1 value of 2?
Let us assume that we can develop a whopping value of a = 1,000,000. We achieve Delta V = C tanh{[Isp/C] ln (Mo/M1)} = C tanh{[a C/C] ln (Mo/M1)} = C tanh{(a) ln (Mo/M1)} = C tanh{[1,000,000 C/C]ln(2)} = C tanh[1,000,000 ln(2)] = C – e where e is 1/(ensemble), which is astoundingly close to C.
We can go yet further and assume a whopping value of a = 1,000,000,000. We achieve Delta V = C Tanh{[Isp/C] ln (Mo/M1)} = C Tanh{[a C/C] ln (Mo/M1)} = C Tanh{(a) ln (Mo/M1)} = C Tanh{[1,000,000,000 C/C]ln(2)} = C Tanh[1,000,000,000 ln(2)] = C – e where e is 1/(an even larger ensemble), which is astoundingly close to C.
We can go yet further still and assume a whopping value of a = 1,000,000,000,000. We achieve Delta V = C Tanh{[Isp/C] ln (Mo/M1)} = C Tanh{[a C/C] ln (Mo/M1)} = C Tanh{(a) ln (Mo/M1)} = C Tanh{[1,000,000,000,000 C/C]ln(2)} = C Tanh[1,000,000,000,000 ln(2)] = C – e where e is 1/(a yet even larger ensemble), which is astoundingly close to C..
In fact, the following limits holds:
Lim v = C
a ---> Infinity , MO/M1 is significantly greater than one
Lim v = C
a ---> Infinity, MO - M1 is at least as great as the mass of the smallest sub-atomic particle
Lim v = C
a ---> Infinity, MO - M1 is any finite value of mass energy
In fact, the following dual limits also hold:
Lim v = C
Lim gamma = infinity
a ---> Infinity , MO/M1 is significantly greater than one
Lim v = C
Lim gamma = infinity
a ---> Infinity, MO - M1 is at least as great as the mass of the smallest sub-atomic particle
Lim v = C
Lim gamma = infinity
a ---> Infinity, MO - M1 is any finite value of mass energy
The following limits hold with loosely defined values:
Lim v = C – e, where e = 1/(ensemble)
Lim gamma = an ensemble
a ---> an ensemble , MO/M1 is significantly greater than one
Lim v = C – e, where e = 1/(ensemble)
Lim gamma = ensemble
a ---> ensemble, MO - M1 is at least as great as the mass of the smallest sub-atomic particle
The following limits hold with loosely defined values:
Lim v = C – e, where e = 1/(infinity scrapper)
Lim gamma = infinity scrapper
a ---> an infinity scrapper , MO/M1 is significantly greater than one
Lim v = C – e, where e = 1/(infinity scrapper)
Lim gamma = infinity scrapper
a ---> infinity scrapper, MO - M1 is at least as great as the mass of the smallest sub-atomic particle
Lim v = C – e, where e = 1/(infinity scrapper)
Lim gamma = infinity scrapper
a ---> infinity scrapper, MO - M1 is at least as great in mass energy as {[(ensemble) EXP -1] eV}.
Now how would a space craft in any of the specific or general examples experience the explosion if by definition of quantum entanglement, the explosion back here in the solar system and the explosion on the extremely relativistic space craft should happen at the same time. If the two explosions indeed happen simultaneously, then the explosion on the craft should in theory happen at a rate and thus with a power output equal to gamma times the rapidity with which the explosion happened back in the solar system and gamma times the power output of the explosion as it occurred in the solar system relative to the solar system reference frame, respectively. In other words, if the explosion took place and was completed in 3 x (10 EXP – 11) second back in the solar system which would correspond to the explosion passing through the solar system based element at a velocity very very close to, and the ships gamma factor was 1 million, then the explosion would appear to take place in only [3 x (10 EXP – 11)]/(10 EXP 6) = 3 x 10 EXP – 17 second on the ship relative to the ship’s reference frame. Thus, for a millimeter sized element, the explosion would appear to progress at a rate equal to about 1,000,000 C or about one million times the speed of light assuming that both explosions are truly entangled and take place in a truly entangled manner.
Alternatively, the explosion on the ship might appear to progress 1 million times more slowly relative to an observer back here in the solar system than it would appear relative to an observer on the space craft. One would assume that the explosions at both locations would appear to begin at the same time for both reference frames, even though they may progress at differing rates that depend on the observer’s reference frame. The explosion aboard the space craft in this case would appear to progress in a normal manner or at a velocity equal to about C and over a time duration equal to about 3 x (10 EXP – 11) second relative to the space craft’s reference frame.
Now what if the explosion back here in the solar system could be made so energetic that one or more microscopic black holes form from the circuit thus effected before the state of entanglement had a change to fully collapse? Perhaps, the conjugate pair circuit element on the space craft would likewise produce one or more black holes in an identical geometric or nearly so relationship with the element back here on Earth.
We can look at thsee possible novel forms of entanglement from the reverse perspective.
Imagine that the millimeter scaled circuit was blasted to an energized state in only 3 x (10 EXP – 11) seconds aboard a space craft (traveling at a gamma factor of 1,000,000) relative to the space craft reference frame. It would seem that the observer back here on Earth would observe the process to take [3 x (10 EXP -11)](10 EXP 6) seconds or 3 x 10 EXP 5 seconds since the process of the explosion on the ship would be dilated by a factor of one million with respect to the observer back in our solar system. If the explosion was alternatively observed to be completed back in the solar system before it was completed on the space craft, the possibility of the final effects of the explosion back here in the solar system occurring before they did in the space craft, at which location the whole process of the dual explosions was initiated to begin with, would seem to violate the temporal order of cause and effect. Thus, we would seem to run into issues of causality of a final state occurring in one location back here in the solar system before it terminated on the space craft wherein the whole process was caused by the explosive action on the space craft.
These examples may need to be considered as real possibilities if the phenomenon of entanglement is truly spooky action at a distance and entangled systems that are widely separated can remain entangled even well into the onset of the explosive destruction of the system.
These speculations are a bit spooky, but if the conjectured kinematical phenomenon are real, then we have in theory, one heck of a rocket fuel, wherein space craft could truly reach arbitrarily high gamma factors.
For those of you who think the above conjectures are off base, I suggest that you listen to Elton Johns popular song “Rocket Man” and speculate about rocket propulsion in your free time. You might and likely can come up with some concepts that are even more extreme then the one’s conjectured about in this article.
I must say listening to the song “Rocket Man” a few years ago caused me to renew my fascination with interstellar travel via good old fashioned rocket science, albeit extreme rocket science or rocket science on steroids.
Regards;
Jim
No, this experiment doesn't prove any theory that was not already known. Quantum entanglement was already a very well-established and commonly studied phenomenon. This is just a demonstration of that phenomenon at a larger scale than anyone has demonstrated it before, that's all.
Also, "theory" and "certainty" aren't really contrasting terms. "Theory" does not mean "hypothesis". A theory is just a body of concepts that fit together. They may or may not be proven.
James Essig:
No, that's not what entanglement means. Entanglement does not involve or allow the instantaneous transfer of energy or information from one place to another, ever, in any form. If you think it does, you're not correctly understanding the meaning of the word.
Entanglement is when you have two things whose states are related in a special way, such that measuring one will cause the other to be in a "measured" state as well. Since it is not possible to determine whether the other is in a "measured" state or not, this doesn't allow information to be transferred. The idea that energy is somehow tranferred between them, or that moving one of them around somehow moves the other around like some kind of crazy puppet, is laughably wrong.
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