### How to build a Star Trek transporter

Randomness and probability are at the heart of my book Dice World and they are also fundamental to quantum theory, which is why I spend some time on the subject in the book. One of my favourite aspects of quantum theory is quantum entanglement (I wrote The God Effect on the subject), which is responsible for a number of interesting technical developments including a small-scale version of the Star Trek transporter.

Think for a moment of what’s involved in such a technology. On Star Trek, the transporter appears to scan an object or person, then transfers them to a different location. This was done on the TV show to avoid the cost of the expensive model work that was required at the time, before the existence of CGI, to show a shuttle landing on a planet’s surface. But it bears a striking resemblance to something that is possible using entanglement.

To make a transporter work, we would have to scan every particle in a person, then to recreate those particles at a different location. There are two levels of problem with this. One is an engineering problem. There are huge numbers of atoms in a human body – around 7 × 1027 (where 1027 is 1 with 27 zeros following it). Imagine you could process a trillion atoms a second. That’s pretty nippy. But it would still take you 7 × 1015 seconds to scan a whole person. Or to put it another way, around 2 × 108 years. 200 million years to scan a single person. Enough to try the patience even of Mr Spock.

Assuming, though, we could get over that hurdle – or only wanted to transport something very small like a virus – there is a more fundamental barrier. What you need to do to make a perfect copy of something is to discover the exact state of each particle in it. But when you examine a quantum particle, the very act of making a measurement changes it so that you can't make a copy. It isn’t possible to simply measure up the properties of a particle and reproduce it. However, quantum teleportation gives us a get-out clause.

There is a slightly fiddly process using entanglement that means we can take the quantum state of one particle and apply it to another particle at a different location. The second particle becomes exactly what the first particle had been in terms of its quantum properties. But we never discover what the values are. The entanglement transfers them without us ever making a measurement. Entanglement makes the impossible possible. This has been demonstrated many times in experiments that range from simple measurements in a laboratory to a demonstration that used entanglement to carry encrypted data across the city of Vienna.

Even if we were able to get around the scanning scale problem, though, it’s hard to imagine many people would decide to abandon cars or planes and use a quantum teleporter for commuting. Bear in mind exactly what is happening here. The scanner will transfer the exact quantum state of each particle in your body to other particles at the receiving station. The result will be an absolutely perfect copy of your body. It will be physically indistinguishable, down to the chemical and electrical states of every atom inside it. It will have your memories and will be thinking the same thoughts. But in the process of stripping those quantum properties, every atom of your body will have been scrambled. You will be entirely destroyed in the process. As far as the world is concerned you will still exist at the remote location – but the original ‘you’ will be disintegrated.

I think I'll stick with the train.

### Why I hate opera

If I'm honest, the title of this post is an exaggeration to make a point. I don't really hate opera. There are a couple of operas - notably Monteverdi's Incoranazione di Poppea and Purcell's Dido & Aeneas - that I quite like. But what I do find truly sickening is the reverence with which opera is treated, as if it were some particularly great art form. Nowhere was this more obvious than in ITV's recent gut-wrenchingly awful series Pop Star to Opera Star , where the likes of Alan Tichmarsh treated the real opera singers as if they were fragile pieces on Antiques Roadshow, and the music as if it were a gift of the gods. In my opinion - and I know not everyone agrees - opera is: Mediocre music Melodramatic plots Amateurishly hammy acting A forced and unpleasant singing style Ridiculously over-supported by public funds I won't even bother to go into any detail on the plots and the acting - this is just self-evident. But the other aspects need some ex

### Is 5x3 the same as 3x5?

The Internet has gone mildly bonkers over a child in America who was marked down in a test because when asked to work out 5x3 by repeated addition he/she used 5+5+5 instead of 3+3+3+3+3. Those who support the teacher say that 5x3 means 'five lots of 3' where the complainants say that 'times' is commutative (reversible) so the distinction is meaningless as 5x3 and 3x5 are indistinguishable. It's certainly true that not all mathematical operations are commutative. I think we are all comfortable that 5-3 is not the same as 3-5.  However. This not true of multiplication (of numbers). And so if there is to be any distinction, it has to be in the use of English to interpret the 'x' sign. Unfortunately, even here there is no logical way of coming up with a definitive answer. I suspect most primary school teachers would expands 'times' as 'lots of' as mentioned above. So we get 5 x 3 as '5 lots of 3'. Unfortunately that only wor

### Which idiot came up with percentage-based gradient signs

Rant warning: the contents of this post could sound like something produced by UKIP. I wish to make it clear that I do not in any way support or endorse that political party. In fact it gives me the creeps. Once upon a time, the signs for a steep hill on British roads displayed the gradient in a simple, easy-to-understand form. If the hill went up, say, one yard for every three yards forward it said '1 in 3'. Then some bureaucrat came along and decided that it would be a good idea to state the slope as a percentage. So now the sign for (say) a 1 in 10 slope says 10% (I think). That 'I think' is because the percentage-based slope is so unnatural. There are two ways we conventionally measure slopes. Either on X/Y coordiates (as in 1 in 4) or using degrees - say at a 15° angle. We don't measure them in percentages. It's easy to visualize a 1 in 3 slope, or a 30 degree angle. Much less obvious what a 33.333 recurring percent slope is. And what's a 100% slope