Kingfisher |

When I started my own blog I decided to focus on 3 of my passions in life, birds, physics and gardening. While this totally bizarre combination is likely to be hellishly boring to most normal sane people, I thought it would at least guarantee a certain uniqueness!

Standlake Pit 60 is my default local birding patch being only a short drive from my home. I have been watching and photographing birds here for some 6 years since my retirement from full time tedium. Having observed six cycles of the seasons at pit 60 I have a calendar in my mind of what I hope to see and photograph when and September and October are Kingfisher time.

We have 3 bird perches outside the Langley lane hide used by Common Terns in the summer and Kingfishers mainly in autumn. Kingfishers need clear water to fish and the Thames in autumn tends to be greenish and opaque while the water at pit 60 is crystal clear. It is said that female Kingfishers wear lipstick as the male has a black lower mandible while the females is orange. Somewhat confusingly, juveniles also have black lower mandibles. I believe my picture is a juvenile based on the greenish appearance of the crown feathers and the dark appearance of its legs.

Kingfisher |

A family of little grebes has recently regularly entertained me during my visits to pit 60. Today I heard a high-pitched strange squeaky call which I could not immediately place until the culprit, one of the four juvenile little grebes, came into view calling to its parents. It then managed to catch and very slowly swallow what was, at least relative to the bird’s diminutive size, a fairly large fish!

Juvenile Little Grebe |

Winter wildfowl are starting to return with the whistle call of Widgeon being heard for the first time since early spring and Teal feeding on the lake margins.

Returning Teal |

Chiffchaffs are also singing again intermittently from the hedgerows around pit 60. My friendly neighbour and mega-birder Mick tells me that it is often this years fledglings that sing in the autumn. For what purpose it is hard to image apart from perhaps practising defending territories and attracting mates next spring.

Grey Wagtail |

So here we go again, look away now if my physics ramblings bore you to death!

I mentioned before something called quantum entanglement. While this is a truly weird and mind blowing phenomena, even by quantum mechanics standards, it is a concept at the heart of quantum information technology, a technology that industry and governments are pouring billions of dollars a year into.

So what’s so exciting about quantum information technology? Google are developing a quantum computer – more on what this is later. The Google quantum computer has just solved a problem in 3 minutes and 20 seconds that would take an estimated 10,000 years on the fastest traditional supercomputer in the world! So they are very fast and can do extremely complex calculations very quickly.

To try and explain quantum entanglement lets use an analogy. Imagine I have 2 children’s spinning tops and I set one rotating clockwise and one rotating anticlockwise on my table. This is a very simple (deterministic) system in that whether I look at them or not it is clear that one will continue to spin clockwise and one will spin anticlockwise.

Now imagine I do the same with two elementary particles whose motion is governed by quantum mechanics, i.e. one particle is spinning clockwise and one is spinning anticlockwise. If they satisfy certain other conditions their very existence is said to be entangled. Bizarrely what this means is that until you actually make a measurement to see which direction one is spinning in they are both spinning both ways in what physicists call a superposition of states. Only when I measure the spin of one is the spin of the other forced to be the opposite!

Very strange as it may seem this has been proven by experiment and entangled quantum pairs are the basic units of a quantum computer replacing the binary 1 and 0 used in existing computers. It turns out that, because these so called qbits can be 1, 0 and states in-between, a quantum computer is exponentially faster that a classic computer with the same number of bits.

By now any sane reader will have decided that this is all rubbish and will be checking what’s on netflicks! Just incase anyone out there is still reading this, let me finish on something even weirder that ties into my previous blogs about physics.

It turns out that you can separate the two parts of the entangled pair by any arbitrary distance and still measuring one to see which way it is spinning immediately forces the other one to be the opposite. If you remember a previous blog I said that Einstein’s relativity says that no information can be transferred faster than the speed of light. So how is the information that a measurement has been made on one part of the entangled pair transported to the other if they are an arbitrary distant apart? This question goes to the heart of the problem of unifying relativity and quantum mechanics into one grand theory.

There are a couple of unproven suggestions as to how this might work. Firstly, the quantum world is really deterministic as some deep level that we do not yet understand (the so called hidden variables theory that Einstein preferred). Secondly, the many worlds theory that says that each time the measurement is made the universe splits into two with one representing the second particle spinning one way and one the other. Thirdly, that the entangled pair are connected by a mico-wormhole that acts as a short cut through space-time. The last in many ways seems the most promising but current calculations indicate that the wormhole would be much too small for anything to pass through.

At this point I cant believe anyone is still reading and awake so its time to stop!!

Understood the birds more than the physics!

ReplyDeleteAs a former quantum mechanic myself I read all the way through! Is it not the case that the point about physically separated entangled pairs is that whilst there seems to be this sudden transfer of "information" from one pair to the other when determining the state, it's not possible to transfer actual information in this way. If you have two observers one at each separated pair, then one couldn't tell the other something via this means. The best that they can do is that by each measuring the state of their particle, they know what state the other's particle must be.

ReplyDeleteAs far as the mechanism of how this works, I've never like the Many Worlds Theory - it just seems a cop-out. In fact, does there actually have to be a physical means for transferring information between the two. Quantum Mechanics is so weird already, perhaps this apparent "action at a distance" is just part of the "cosmic oneness". It's like a single particle interfering with itself in the classic Two Slit experiment. In fact the more one delves into this sort of stuff the more metaphysical it all gets!

[Jim has asked me to post the following comment on his behalf as for some reason he can't post it himself]

ReplyDeleteHi Adam,

Many thanks for taking the time to read my blog and for your insightful comments.

I did a grad course on the philosophy of quantum mechanics taught by Tony Legget who subsequently won the Nobel prize for his theoretical work on quantum mechanics. Unfortunately the interving 40 years have wiped all knowledge of this from me!

On the non-locaity issue with entangled pairs your argument seems very valid!

There was a very interesting article in new scientist a few weeks ago about entanglement. Basically it said that most attempts to unify quantum mechanics and general relativity start off my quantising space time and then attempt to derive the equations of general relativity from this. This article was written by someone who had taken a different approach. If I understood correctly he started from the assumption that entanglement is the fundamental property of the universe and managed to derive the equations of general relativity from this assumption.

Cheers

jim

[Again, posted on Jim's behalf]

ReplyDeleteHi Adam,

I was thinking about the entangled pair some more …

When they are entangled they are in a superposition of states represented mathematically by the wave function. In the Copenhagen interpretation until a measurement is made neither particle is in a deterministic state. As soon as you measure the properties of one particle the wave function collapses and the other particle drops into the opposite state. In this sense the information that the wave function has been collapsed at one particle still instantaneous must be transmitted to cause the total collapse of the wave function at the other particle?

cheers

Jim