This week, researchers from the UK, Canada and Singapore have accomplished quantum entanglement on the macro scale, entangling two millimeter-sized diamonds.
Typically we think of objects moving and interacting according to classical mechanics – i.e. Newton’s Second Law – you apply a force to one object and it will cause it to accelerate in a particular direction. But in quantum mechanics there are extra complications, such as entanglement, where an action performed on one object will affect another - even if they are at a distance: something described by Einstein as ‘spooky’.
Studying these quantum effects on objects any larger than an atomic particle is tough because there is so much environmental noise. Once in the ‘macroscopic’ scale, there are too many extra factors which are difficult to eliminate. The usual approach is to lower the temperature and so reduce thermal noise. Publishing in the journal Science, a team led by Ian Walmsley of Oxford University, took millimetre-wide pieces of diamond and tried to look at them in a more typical environment with an ambient temperature. To get around the problem of other noisy interactions that could interfere with results, they shortened the experiment to a matter of femtoseconds, and they did this using laser pulses.
Next came the entanglement, which they achieved by setting up a beam-splitter and detectors. They fired two laser pulses at each diamond, 350 femtoseconds apart. The second pulse picked up the energy the first pulse left behind before reaching the detector as an especially-energetic photon. If the system were classical, the second photon should pick up extra energy only half the time – only if it happened to hit the diamond where the energy was deposited in the first place.
But in 200 trillion trials, the team found that the second photon picked up extra energy every time. That means the energy was not contained within each diamond, but that they shared the same state as if they were one system. It had already been predicted that this could be done with larger objects at ambient temperature, but actually doing it is something else altogether so – although brief - this may be a step towards some real-world quantum computing, where entanglement allows you to store far more complex information than binary digits.
fractal geometry in forest?psychic entanglement of biotwins? clone might do better? CZARCAR, Mon, 5th Dec 2011
So what created that entanglement?
Very nice question Clifford. Depends on how you look at it I guess :) I would say that they define it as it is the diamonds that now are entangled. The problem might then be that if they are, the entanglement then should cover the whole of the system? Meaning that this light pulse/photons sent that somehow not is expected to disperse into the whole of the diamond(s) under the firings, later, when looked at the whole experiment yet..Is expected.. to cover the same whole that earlier was treated as 'pinpointing'? yor_on, Wed, 7th Dec 2011
You might want to look at it as a result of 'wave functions'. Then the diamonds disappear, instead you have a mathematical equation symbolizing the 'system'. In the case of before firing you then will have two wave functions describing each one of the diamonds (ignoring laser etc). After the firing the diamonds represent one same wave function mathematically if entangled. That is on a theoretical plane though, not considering that those diamonds actually is there at all times. yor_on, Wed, 7th Dec 2011
Ahh sweet, they split the light in a beam splitter, so the light hitting the diamonds are/is already entangled :) as it has a same origin. Then what you do to one 'side' of the 'wave function' that this light (now split into two parts but still being one wavefunction) represent should be reflected in the other 'side'.
http://www.scientificamerican.com/article.cfm?id=room-temperature-entanglement CZARCAR, Wed, 7th Dec 2011
Very nice Czarcar.