Don’t fall for quantum hype

#Dont #fall #quantum #hype

Quantum technology is presently amazingly popular.  The United States and the United Kingdom have made   it a „national initiative”, the European Union  has a quantum technology “flagship.” India has   a “national mission”, and China has announced  they’ll put quantum technology into their next  

5 year plan. What is “quantum technology”  and what impact will it have on our lives?   That’s what we will talk about today. Don’t fall for Quantum Hype The quantum initiatives differ  somewhat from nation to nation,   but they usually contain research programs on four  key topics that I will go through in this video.  

That’s: quantum computing, the quantum internet,  quantum metrology, and quantum simulations. We’ll start with quantum computing. Quantum computing is one of the most interesting  developments in the foundations of physics right   now. I have talked about quantum computing  in more detail in an earlier video,  

So check this out for more. In brief,  quantum computers can speed up certain   types of calculations dramatically. A quantum  computer can do this because it does not work   with “bits” that have values of either 0  or 1, but with quantum bits – “qbits” for  

Short – that can be entangled, and can  take on any value in between 0 and 1. It’s not an accident that I say “between” instead  of “both”, I think this describes the mathematics   more accurately. Either way, of course, these  are just attempts to put equations into words  

And the words will in the best case give  you a rough idea of what’s really going on.   But the bottom line is that you can process much  more information with qbits than with normal bits.   The consequence is that quantum computers  can do certain calculations much faster  

Than conventional computers. This speed-up only  works for certain types of calculations though.   So, quantum computers are  special purpose machines. The theory behind quantum computing is  well understood and uncontroversial.   Quantum computers already exist and so  far they work as predicted. The problem  

With quantum computers is that for them to become  commercially useful, you need to be able to bring   a large number of qbits into controllable quantum  states, and that’s really, really difficult.  Estimates say, the number we need to reach is  roughly a million, details depend on the quality  

Of qbits and the problem you are trying to solve.  The status of research is presently at about 50   qbits. Yes, that’s a good start, but it’s a long  way to go to a million and there’s no reason to   expect anything resembling Moore’s will help us  here, because we’re already working on the limit.

So, the major question for quantum computing  is not “does it work”. We know it works.   The question is “Will it scale”? To me the situation for quantum   computing today looks similar to the situation  for nuclear fusion 50 years ago. 50 years ago,  

Physicists understood how nuclear fusion works  just fine, and they had experimentally checked   that their theories were correct. The problem  was “just” to make the technology large and   still efficient enough to actually be useful. And,  as you all know, that’s still the problem today.

Now, I am positive that we will eventually  use both nuclear fusion and quantum computing   in everyday life. But keep in mind that  technology enthusiasts tend to be overly   optimistic in their predictions for how long  it will take for technology to become useful. The Quantum Internet

The quantum internet refers to information  transmitted with quantum effects.   This means most importantly, the quantum internet  uses quantum cryptography as a security protocol.   Quantum cryptography is a method  to make information transfer secure   by exploiting the fact that in quantum mechanics,  a measurement irreversibly changes the state of  

A quantum particle. This means if you encode a  message suitably with quantum particles, you can   tell whether it has been intercepted by a hacker,  because the hacker’s measurement would change the   behavior of the particles. That doesn’t prevent  hacking, but it means you’d know when it happens.

I made an entire video about how  quantum cryptography works, so   check this out if you want to know more.  Today I just want to draw your attention to   two pointes that the headlines tend to get wrong. First, you cannot transfer information faster  than the speed of light with the quantum internet  

Or with any other quantum effect. That  quantum mechanics respects the speed   of light limit is super-basic knowledge that  you’d think every science writer knows about.   Unfortunately, this is not the case. You see this  over and over again in the headlines, that the  

Quantum internet can supposedly beat the speed  of light limit. It cannot. That’s just wrong.  And no, this does not depend on your  interpretation of quantum mechanics,   it’s wrong either way you look at it. No,   this is not what Einstein meant with “spooky  action at a distance”. It’s really just wrong.  

Quantum mechanics does not allow you to send  information faster than the speed of light. This isn’t the major issue I have with the  coverage of the quantum internet though,   because that’s obviously wrong and really  what do you expect from the Daily Mail. No,  

The major issue I have is that almost all  of the of the articles mislead the audience   about the relevance of the quantum internet. It’s not explicitly lying, but it’s lying by   omission. Here is a recent example  from Don Lincoln who does exactly this,  

And pretty much every article you’ll read about  the quantum internet goes somewhat like this. First, they will tell you that quantum computers,  if they reach a sufficiently large number of   qbits, can break the security protocols that are  currently being used on the internet quickly,  

Which is a huge problem for national  security and privacy. Second,   they will tell you that the quantum internet  is safe from hacking by quantum computers. Now, these two statements separately are entirely  correct. But there’s an important piece of   information missing between them, which is that  we have security protocols that do not require  

Quantum technology but are save from quantum  computers nevertheless. They are just presently   not in use. These security protocols that, for  all we currently know, cannot be broken even   by quantum computers are, somewhat confusingly,  called “post-quantum cryptography” or, in somewhat   better terminology, quantum-safe cryptography. This means that we do not need the quantum  

Internet to be save from quantum computers.  We merely need to update the current security   protocols, and this update is already under way.  For some reason the people who work on quantum   things don’t like draw attention to that. Quantum metrology

Quantum metrology is a collection of techniques to  improve measurements by help of quantum effects.   The word “metrology” means that this  research is about measurement; it’s got   nothing to do with meteorology, different thing  entirely. Quantum metrology has recently seen  

Quite a few research developments that I expect  to become useful soon in areas like medicine   or material science. That’s because one of  the major benefits of quantum measurements   is that they can make do with very few particles,  and that means minimal damage to the sample.

Personally I think quantum metrology is the most  promising part of the quantum technology package   and the one that we’re most likely to  encounter in new applications soon.  I made a video especially about quantum metrology  earlier, so check this out for more detail. Quantum Simulations

Quantum simulations are a scientifically  extremely interesting development that I think   has been somewhat underappreciated. In a quantum  simulation you try to understand a complicated   system whose properties you cannot calculate,  by reproducing its behavior as good as you can  

With a different quantum system that you can  control better, so you can learn more about it.  This is actually something I have worked on myself  for some years, in particular the possibility that   you can simulate black holes with superfluids.  I will tell you more about this some other time,  

For today let me just say that I think this is  a rather dramatic shift in the foundations of   physics because it allows you to take out  mathematics as the middleman. Instead of   modeling a system with mathematics, either with a  pen on paper or with computer code, you model it  

Directly with another system without having to  write down equations in one form or another. Now, quantum simulations are really cool  from the perspective of basic research,   because they allow you to learn a great deal.  You can for example simulate particles similar  

To the Higgs or certain types of neutrinos,  and learn something about their behavior,   which you couldn’t do in any other way. However, quantum simulations are unlikely to have   technological impact any time soon, and, what’s  worse, they have been oversold by some people  

In the community. Especially all the talk about  simulating wormholes is nonsense. These simulated   “wormholes” have nothing in common with actual  wormholes that, in case you missed it, we have   good reason to think do not exist in the first  place. I am highlighting the wormhole myth because  

To my shock I saw it appear in a white house  report. So, quantum simulations are cool for   the most part, but if someone starts babbling  about wormholes, that is not serious science. I hope this quick summary helps you make sense  of all the quantum stuff in the headlines.

This video was sponsored by Brilliant which  is a website and app that offers interactive   courses on a large variety of topics in science  and mathematics. Brilliant is a great starting   point if you want to know more about quantum  mechanics. They have you covered on the math  

Behind quantum mechanics, such as linear algebra  and differential equations, and they have courses   on the properties and behavior of quantum objects  and even on quantum computing in particular. To support this channel and  learn more about Brilliant,   go to brilliant dot org slash Sabine and  sign up for free. The first 200 subscribers  

Using this link will get 20 percent  off the annual premium subscription. Thanks for watching, see you next week.