Physicist unveils plan for entangling massive objects

August 5, 2015 by Bob Yirka report
Physicist unveils plan for entangling massive objects
Illustration of the Michelson interferometer setup for the generation of an EPR-entangled motion of two massive mirrors that are suspended as pendula. If the mirrors are well isolated from the environment, radiation pressure leads to entanglement between the motion of the mirror and the field quadratures of the reflected light field in each arm. Superimposing the two light fields and balanced homodyne detection at the two output ports (1, 2) enables entanglement swapping that continuously generates an EPR-entangled motion of the mirrors. Residual coupling to the environment continuously destroys the entanglement, such that the entanglement will be present continuously but only over some finite short-time interval. To achieve the required state purity at nonzero temperatures, conditional states of motion need to be defined. Credit: Phys. Rev. A 92, 012126 – Published 28 July 2015. DOI: 10.1103/PhysRevA.92.012126

(Phys.org)—Roman Schnabel, a physics professor at the Max Planck Institute for Gravitational Physics has published a paper in the journal Physical Review Letters outlining a plan for entangling two "massive" objects. He and his team are still working on a way to actually carry out the plan, but if successful, the group would succeed in entangling two 0.1 kg mass mirrors, which would represent a much larger example of entanglement than anything that has come before—up till now the largest objects to be entangled were of micron size.

Entanglement is of course the odd and perhaps a little eerie situation where two or more objects are connected in a way that cannot yet be explained—measuring one causes the other to be impacted instantaneously. The phenomenon was predicted back in the 1930's by Einstein, Podolsky, and Rosen. Over the years, scientists have developed ways to cause particles and then tiny objects to become entangled, but it still was not clear if a way could be found to cause objects large enough to be governed by classical physics to be entangled. In his paper, Schnabel draws up a means of achieving that goal, and notes that he believes it can be done.

Schnabel's plan is to place two of the mirrors in a Michelson-type interferometer in such a way as to have both sides of both mirrors hit by that is sent in. The mirrors would also be placed in the interferometer in a way that would allow them to oscillate when struck by the light. This would allow for momentum to be transferred between the mirrors and the light. The mirror oscillations would then have an impact on the phase of the reflected light, causing the momentum and the light to become entangled. At that point, the entanglement could be "swapped" to the mirrors, causing them to be entangled, by measuring the light beams as they exit.

Testing that has occurred, he continues, could be done by switching off the light source to let the system proceed for a very short period of time before taking another measurement and then repeating it after one of the beam splitters has been turned off—over and over again.

Schnabel notes that there are several challenges that must be overcome before the experiment can be carried out, such as cooling the and preventing them from being impacted by the surrounding environment.

Explore further: Quantum memory for communication networks of the future

More information: Einstein-Podolsky-Rosen–entangled motion of two massive objects, Phys. Rev. A 92, 012126 – Published 28 July 2015. journals.aps.org/pra/abstract/10.1103/PhysRevA.92.012126

ABSTRACT
In 1935, Einstein, Podolsky, and Rosen (EPR) considered two particles in an entangled state of motion to illustrate why they questioned the completeness of quantum theory. In past decades, microscopic systems with entanglement in various degrees of freedom have successfully been generated, representing compelling evidence to support the completeness of quantum theory. Today, the generation of an EPR-entangled state of motion of two massive objects of up to the kilogram scale seems feasible with state-of-the-art technology. Recently, the generation and verification of EPR-entangled mirror motion in interferometric gravitational wave detectors was proposed, with the aim of testing quantum theory in the regime of macroscopic objects, and to make available nonclassical probe systems for future tests of modified quantum theories that include (nonrelativistic) gravity. The work presented here builds on these earlier results and proposes a specific Michelson interferometer that includes two high-quality laser mirrors of about 0.1 kg mass each. The mirrors are individually suspended as pendula and located close to each other, and cooled to about 4 K. The physical concepts for the generation of the EPR-entangled center-of-mass motion of these two mirrors are described. Apart from a test of quantum mechanics in the macroscopic world, the setup is envisioned to test predictions of yet-to-be-elaborated modified quantum theories that include gravitational effects.

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21 comments

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TopCat22
not rated yet Aug 05, 2015
mirror mirror on the wall can we look through you near and far
docile
Aug 05, 2015
This comment has been removed by a moderator.
bearly
not rated yet Aug 05, 2015
Possible transporter?
OdinsAcolyte
3 / 5 (2) Aug 05, 2015
Tricky. I do not understand how they will do the swap. Very, very tricky.
The implications are....weeeee.
OdinsAcolyte
1 / 5 (1) Aug 05, 2015
Tricky. I do not understand how they will do the swap. Very, very tricky.
The implications are....weeeee.
Returners
2.3 / 5 (3) Aug 05, 2015
Yet another Entanglement experiment which literally amounts to "smoke and mirrors".
Doug_Huffman
5 / 5 (1) Aug 05, 2015
"[M]ass mirrors" are a special kind of 0.1 kg mirrors.
docile
Aug 05, 2015
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docile
Aug 05, 2015
This comment has been removed by a moderator.
docile
Aug 05, 2015
This comment has been removed by a moderator.
docile
Aug 05, 2015
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arom
2.3 / 5 (3) Aug 05, 2015
Entanglement is of course the odd and perhaps a little eerie situation where two or more objects are connected in a way that cannot yet be explained ….

Over the years, scientists have developed ways to cause particles and then tiny objects to become entangled, but it still was not clear if a way could be found to cause objects large enough to be governed by classical physics to be entangled….


This seems to be something like professor Feynman had tried to prove the wave property of gun's bullets with two slits interference experiment in quantum mechanics .…
http://www.vacuum...19〈=en
antialias_physorg
4 / 5 (4) Aug 05, 2015
Possible transporter?

Nope. But possible very, very sensitive measuring device.
docile
Aug 05, 2015
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qitana
5 / 5 (1) Aug 05, 2015
is the entanglement of atoms or molecules as easily broken as that of macroscopic objects?

cause if it isn't and the experiment would work, might it be possible to build a more stable quantum computer?
docile
Aug 06, 2015
This comment has been removed by a moderator.
Returners
2.3 / 5 (3) Aug 06, 2015
I can demonstrate a situation where a classical system can have two orientations simultaneously, just like a so-called quantum system.

It's simple. Get a coin and a glass table top, and a mirror.

Put the coin on top of the table and put the mirror beneath it. Now the coin is both heads up and tails up.

Neat.
Noumenon
5 / 5 (3) Aug 07, 2015
If you think you can find a classical analogy that reproduces the quantum superposition effect in terms of subsequent observation ,.... then you don't understand quantum mechanics.

If the above experiment becomes a practical reality, perhaps Penrose's idea of quantum Objective Reduction (physical collapse of a physical wave-function) could be experimentally tested,.... where energy of gravitational curvature between entangled particles collapses the wave-function.
Noumenon
5 / 5 (1) Aug 07, 2015
.... out is space near a massive object, I would imagine.
EWH
5 / 5 (1) Aug 09, 2015
Sounds pretty much like this:
Quantum Opto-Mechanics with Micromirrors: Combining Nano-Mechanics with Quantum Optics
Simon Gröblacher, Springer 2012
https://books.goo...;f=false

Schnabel (at Planck) appears in many of the same bibliographies as Gröblacher (at Vienna), but not the same papers, so they seem to be competitors.
Hyperfuzzy
5 / 5 (1) Aug 10, 2015
What they are saying is: Any object in space may be seen as that object in space, i.e. the fields have no effect, unless destructive. So, if you're looking at yourself, you expect what! Are you trying to confuse me? Is this a minimal destructive test to obtain propulsion? Why not create matter with opposite rotators and thrust it into an energy absorption container that converts impact ton inverse momentum! But why not simply control the field and release based upon the field of existence, or an existent(t) anywhere?

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