Rediscovered a talk by Ross Anderson dismissing quantum mechanics and hence quantum computing.
His very first words are: I was invited here to provide a dissenting view.
He is basically saying that quantum mechanics are not different from classical physics. That’s what Bohm/De Broglie pilot wave theory argues but it has been dismissed many times by the scientific dogma in favor of the string theory although it keeps coming back again and again. Anderson’s argument is that you should have as much success computing with water waves as with quantum computers.
There are couple of thoughts going through the talk, first he models quantum mechanics based on fluid dynamics which makes it easy to understand behavior of matter at that scale, second he uses old de Broglie and Bohm’s pilot wave theory to explain quantum behavior. If anything, the experiment done at MIT and several other universities makes you question what we know about how the universe works and whether we understand behavior at quantum scale. There are many warning signs for engineers developing quantum computers. Whether they succeed or fail, they will undoubtedly advance our knowledge.
The problem though with both Quantum and Classical models is that they are approximations of how the world works, they do not give exact blueprint which would allow to reconstruct the universe. Modern division of matter into particles and waves is a mistake although it may be convenient and intuitive for teaching children. There are no separate particles and waves, there are no lego-like building blocks which we call particles from which we and everything else is made, there are no bricks with hidden magical and weird properties in nature which can be used to assemble structures, like kids would do, and then animate them like Gods breathing the breath of life into them. We and everything in the universe is made from pure energy which can be held together and take various shapes, properties, and behaviors and which can manifest itself and be concentrated in point-like properties as well as demonstrate wavy interference patterns. Hints of this are in observations including the experiments described below.
Energy does not transform into mass, there is no mass-energy equivalence. Energy has mass. Mass is inseparable from energy, mass is a type of force. If that were not the case we would be talking about some bricks from which matter is made which is nonsense.
It is nonsensical to talk about intelligent life and ask questions like: Are we alone in the universe? The universe is itself alive and can create anything it wants. Life on earth including us and consciousness are extensions of forms through which the universe achieves its goals. There is no mind-body duality. Mind is part of the structure of energy of the universe. Energy has mind just like it has mass.
One more time, energy can be held together by forces to create various structures like galaxies, stars, planets, and animals, and it can contain mind and mass depending on its configuration.
Modern theory that time is a dimension in space-time is another unhelpful theory whether its math makes correct predictions or not. Like Feynman said before: You can have perfect math while your physics is crap. Time is not a dimension, it is not a vector through which space can move back and forward. Time is a scalar which indicates the rate of change. This rate of change can vary in presence of other variables which is what has been observed with atomic clocks.
Before watching Anderson’s talk I recommend you to get familiar with several more concepts.
- Watch a talk by Jim Baggott discussing the concepts of mass.
- Listen to Wallace Thornhill from the electrical universe project.
- Watch Seeing atoms and electrons with an electron microscope by Frank Close (1993).
- Here’s the video of the MIT pilot-wave dynamics of walking droplets.
Should a prudent cryptographer believe all the quantum claims?
Why Quantum Computing doesn’t work
The QC community believes:
- Classical systems obey the Bell inequalities
- Quantum systems don’t, and this has been verified with photons
- Therefore there are weird things going on, such as multiple universes, that we can surely harness to do useful work
But classical fluids don’t obey the Bell inequalities. Solutions on a phase vortex behave in exactly the same way that quantum mechanics predicts for photons and that is observed in the Bell tests.
You don’t need weird magic like multiple universes and time travel. All you need is long-range order.
My own background, I started off as a pure mathematician, I got into cryptography and eventually into hardware reverse engineering about 15 years ago. Many of you know me as one of the authors of the AES finalist serpent. I also did work on API security showing that most of the cryptographic hardware security modules available 15 years ago, could be broken by manipulating the APIs. I worked in payment systems, I’ve done work in security Economics, but like the two previous speakers, I’ve also worked with lasers. This is one of the snaps from a paper of 15 years ago, which kept kicked off the field of semi-invasive reverse engineering.
The chip was mounted on an X-Y motorized stage with 0.1 μm resolution. The result of the scan is shown in Figure 84. The active areas can be seen as they produce higher current, but most of the chip is covered with metal layers which the laser cannot penetrate, so these areas do not produce any current. We used this picture as a reference for the results obtained from a powered chip.
What we basically did was we took a laser and scanned across the surface of the smart card chip and the additional leakage current, which was measurable whenever a gate was, meant we could tell the difference between zeros and ones on flip flops, and we could thus red out keys. And for a period of about ten years, this gave us a piece of wonderful quantum magic for extracting keys without using the circuits provided for the purpose. It doesn’t work with modern 22 nanometer processes because they’re too small.
So, quantum physics: is it a threat or a promise?
Now, as we’ve heard, thirty years ago Charles Bennett and Gilles Brassard came up with an idea for a key exchange based on single photons and the Heisenberg Uncertainty Principle. Peter Shor in 1994 came up with a polynomial time factoring on a quantum computer which really got peoples’ attention because if you can factor RSA moduli then of course that makes many of the current public-key crypto systems obsolete and there have been many new tweaks and twists around entanglement since which we’ve heard some of. There’s currently a vision being promoted in certain quarters. It’s that quantum computing makes public-key crypto obsolete and then quantum crypto supplies a replacement technology. And in the UK, for example, our government has given an absolute shed load of money to a number of quantum hubs to pursue this vision, there’s a hub for quantum communication which is trying to out-compete Nicholas’ company by doing more and better quantum crypto, there’s a hub for quantum navigation, and there’s a hub for quantum computation.
What physicist are learning about cryptography, quantum crypto still needs line of sight or continuous fiber which limits you to perhaps a hundred kilometers or perhaps to a friendly satellite and so you get an application that you can rekey the line encryptors from a bank datacenter to the recovery site. But here again, as has been mentioned, the real threats are either poor engineering or subversion. We’ve all heard of the story behind crypto, the NSA if it finds a company becomes too powerful in the market and supplies too many federal governments, they just buy the company, they go to the owners and they say: Here is a 100 million dollars, shut up! Or else, they go to the FISA court and they say: Here is the warrant, give us all your keys or you will go to jail forever and you mustn’t tell anybody anything ever. These are the real threats that we face nowadays.
You can certainly use quantum mechanisms for key generation and I am all in favor of good randomness, and many sources of randomness we use come one way or another from quantum mechanisms. But again, the real threats are around engineering and subversion.
Now what would happen if we eventually got bad guys who could do instant factoring brought by a quantum computer or by some brilliant guy having an idea in elliptic curves? We would probably move from TLS to Kerberos and we have to use Merkle signatures for software updates because in real life applications we’ve got to do stuff and to end. We can’t do stuff point-to-point. And if you really get ‘trusted node’ networks then the real downside of that is that you end up trusting the government. It may be okay in China to have a national network of trusted key servers through which everybody has to go, but it’s not how we have grown up doing the web and doing security online in free democratic countries.
In short, quantum methods can’t solve most real-world crypto problems.
I could say similar things about quantum navigation. This is the field I worked in the 1970s. My first real job was working on the tornadoes and national navigation set. Here too cold atoms give us some absolutely wonderful senses. Cold atom sensor where you split states and measure the interference when they recombine and give you sensitivity of ten nano-g and 200 pico-radians anodes and accuracy of 10-16, which is way, way better than you can do with existing sensors. The only problem is they are big, they are heavy, they are expensive and the only apps that we know of for them are in the submarines. So again, wonderful technology, but it’s not going to change the world.
What about quantum computing? This is the big question. Can somebody build a quantum computer that will work well enough to factor two thousand-bit numbers? Speculation goes back to Dick Feynman in the 1970s and David Deutsch in the 1980s and of course it was Peter Shore who in 1994 got people sit up and take notice with his algorithm. He showed that if you could compute with superposed states, you could find cycles easily and thus do factorization in polynomial time. Since then, despite the expenditure of colossal amounts of money, we have no useful engineering.
D-Wave produced machines that they claim work, they sold one to NASA and Google. NASA and Google tested it exhaustively, they concluded that there was no observable quantum speed up. You can read Scott Aaronson’s blog and conclude what people in the QC community think about D-Wave.
And of course, Ed Snowden gives us the inside track. He says that even the NSA is stuck.
So, what’s going on here? Is there something we’re missing? Is the failure to make quantum computing work actually telling us something about physics? When you get stuck, always try to turn the problem around and see if the frustration turns into evidence.
Here we get to the hard core of the business, the fundamental belief of the quantum computing community is something like this:
- Classical systems obey the Bell inequalities
- Quantum systems don’t obey the Bell inequalities and this has been verified with the photons
- Therefore there are weird things going on, such as multiple universes, that we can surely harness to do useful work.
This actually goes back to Einstein, Podolsky and Rosen (EPR) in 1934. They pointed out in a paper that was for decades was the highest cited paper in physics that if an electron and a positron are generated together by an atomic decay then they get the same wave function until one of them interacts with other particles. But if they move apart first, then if you measure the position of one, you can’t measure the momentum of the other, at least with arbitrary accuracy. And this means that somehow something is being transmitted potentially faster than light. And Einstein really didn’t like that because he had made his bones by talking about speed of light being the universal speed limit. So, Einstein denounced this as ‘spukhafte Fernwirkung’.
It’s really, really hard to do Bell test with electrons and positions because you need to borrow CERN for a year. But in any case, in 1964 the Irish mathematician John Bell proved a bound on the correlation between classical particles, which is exceeded, by quantum mechanical predictions for fermions (electron and positron). But the result that people actually use is ‘CHSH’ invented by John Clauser, Mike Horne, Abner Shimony and Dick Holt in 1969. They made this key assumption that the polarization of each photon is ‘carried by and localized within it’, and if that assumption is true, then they predict a limit on the correlation between the polarization of photons that are generated together and observed at a distance. And quantum mechanics predicts that this too will be exceeded.
In 1974 Freedman and Clauser observed that photons violated the CHSH inequality. The modern form of it is what’s called a two-channel experiment.
Where is the number of correlations between photon pairs measured with polarizers set at angles x and y as shown in the following Bell inequality test schematics.
Here’s what you do you get the half silvered mirrors, you got a photon source that produces correlated photons, and for angles a and b you measure the correlations or , you got inequality there saying that those four correlations have an absolute value less than two.
Quantum mechanics predicts that the correlation will be at an angle and with a little bit of monkeying about, we find that there are angles which will enable this to violate the CHSH inequality!
Set equal to to violate CHSH!
That was observed in 1982 by an Alain Aspect and there have been many, many variants since. So this is, if you like, the scientific basis of this.
But what do the Bell tests mean? Polarization information seems to be travelling faster than light, and that shouldn’t happen. Einstein didn’t like it. But there is to our rescue a ‘no-signaling theorem’ which says that you can’t use this to communicate.
What does this mean in terms of our knowledge of the universe where many people in the quantum computing business hold the multiple universes view of quantum mechanics, that is whenever a measurement is made the universe splits into two – you factor a 2048-bit key by operating in 22048 universes at once. And so, those gazillions and gazillions and gazillions of new universes being created just as I speak. And in fact, every time I fly like a blade of grass a million new universes are created in order to make everything add up.
And I never liked this idea because I’m an old fashion-type physics guy and prefer to believe in the conservation of energy, but the real ‘Now hang on a second moment!’ for me was ‘Delayed Choice Entanglement Swapping’ experiment conducted by Xiaosong Ma, Anton Zellinger, et al., described in Nature 2012.
What they did was to entangle photon A with photon B, and then photon B with photon C, then C with D, and they do the CHSH test and discover that A and D are entangled even though they didn’t exist at the same time. They concluded that you can do entanglement through time as well as through space.
Now, what that says to me is that this information that you can’t use for signaling is actually traveling backwards through time. And then the ‘no-signaling theorem becomes a no-tardis theorem, it says, you can’t use this as a time machine to kill your grandfather. But hang on a minute, in my way of thinking there’s something wrong here.
What other possibilities are there?
I’d like to show a brief video of bouncing droplet experiments.
That’s a series of fascinating experiments that have been done in Paris, in Liege and in the MIT over the past ten years, and those really gave us pause for thought. This is what’s happening. You got an oil bath, you can do it with water but then the droplets evaporate, so it’s not as good for experiment, but you vibrate it at about 30Hz and about 4g peak acceleration, and you see all the quantum phenomena arising naturally in the right parameter region.
Find out more at the following link: Why bouncing droplets are a pretty good model of quantum mechanics by Brady, Robert et al. arXiv:1401.4356 [quant-ph].
This is the sort of thing that you see with a camera.
The Bouncing motion
Most phenomena of interest at double period
The interesting phenomena typically happen a double period so that the blue is the shaking of the oil bath and the red is the bouncing of the droplet.
In 2013, a physicist colleague Robert Brady and I basically spent the summer figuring out how all this works. It’s just one of those times when a problem gets hold of you and it doesn’t let you go. And what we did was to contact the French team and get hold of the raw data which they kindly gave to us. And here’s the photo taken by Suzie Protière (2006).
Deflection from boundary of dish
It shows what happens when a droplet bounces around a rectangular tray. This is a stroboscopic photograph where each dot is basically one time period. As you can see, the droplet bounces off the edge, but the angle of incidence is greater than the angle of reflection.
So we plotted this and the first thing that we observed is that the forces are inverse square which you can do by plotting V Squared over one over r, and you can see that it is at a significant distance from the binary, that’s clearly the inverse square force.
What could possibly be going on here?
In the 1880s there was a Danish guy called Carl Bjerknes. He predicted the inverse square force in 1875 and demonstrated it experimentally in 1880.
He did an interesting experiment in which he got two pigs bladders, put them in a wave tank and inflated and deflated them simultaneously using a pump. He found that there was an inverse square force between them were by in-phase pulsations attract and in antiphase they repel. This is because the force V▽P has a term which is always positive. If you want to see in geometrically look at the plane of symmetry between two bladders, and you can see that the ridges put pressure because of the increased velocity of flow.
This is a well-known phenomenon and you can observe it in an oil degasser which has oil with bubbles in it, you put an ultrasonic transducer in it, vibrate it for a few seconds and see how bubbles will pulsate in phase and merge. This is all elementary fluid dynamics.
For more detail read the paper Why bouncing droplets are a pretty good model of quantum mechanics