Quantum computing - help!

[MooseGoose]

It would be a challenge to express just how deeply ignorant I am of quantum computing.

The word seems to be thrown around rather easily by marketers - knowing a little bit about how tech marketing departments work I am naturally suspicious.

I'd be really keen to know what you guys think of the promises made about quantum computing - is it that revolutionary? will the technology undergirding it ever be implemented on a broad scale? how long will it be (if ever) before we see it rolled out?

As ever, I apologise for being utterly useless

Moose

 

[Daniel Payne]

Moose,

Wikipedia has a nice list of companies doing quantum computing research:

List of companies involved in quantum computing or communication - Wikipedia

A top 18 list of quantum research companies:

What is Quantum Computing ? Top 18 Quantum Computing Companies - Compare Reviews, Features, Pricing in 2018 -PAT RESEARCH: B2B Reviews, Buying Guides & Best Practices

They have to cool the circuits to exhibit quantum behavior near absolute Zero, which takes some effort:

At what temperature do Quantum computers function, and why? - Quora

Every year the researchers announce more bits in their quantum computers.

The hype is high for quantum, while actual results are low in 2018. Quantum computers should be good for cryptography applications.

Big names in quantum include: IBM, Intel, Microsoft, Google.

 

[U235]

It would be a challenge to express just how deeply ignorant I am of quantum computing.

I'd be really keen to know what you guys think of the promises made about quantum computing - is it that revolutionary?

Yes, quantum computing is revolutionary.

But it's not a direct replacement for classical, general purpose computing.

While information in a classical computer is stored and manipulated as bits representing 0 or 1, a qubits of a quantum computer computer can be prepared in a such a way as to represent a superposition of both 0 and 1 together. Performing an operation on a qubit, could be viewed as performing the operation on 0 and 1 at the same time, leading to a sort of (quantum) parallelism.

While a classical computer can store and operate on any single 64 bit word in a register, a 64 qubit register could hold and work on all 2^64 combinations at the same time.

There are some algorithms which could make use of this fact to dramatically speed-up large number factorisation, or sorting etc, as well as for the efficient simulation of quantum systems themselves.

I believe, the largest entangled state achieved in a lab is 18 qubits.

The D-Wave machines which Google, Lockheed martin, and Nasa have bought, aren't conventional quantum computers, but instead implement quantum annealing, and it's pretty controversial as to what they are actually doing.

 

[Brad Pierce]

Quantum computers: “The simulation of quantum systems is an awesome application” – Brad Pierce's Blog

 

[Daniel Nenni]

IBM finally proves that quantum systems are faster than classicals

 

[Bernard Murphy]

Quantum computing shows promise in helping solve quantum problems (unsurprising), so potentially useful in physics, inorganic chemistry and organic chemistry for modestly-sized molecules. Agree with U235 - it is not a replacement for conventional computing.

 

[MooseGoose]

Thanks all for your answers!

One more question - if we agree that Quantum computing is indeed a sort of revolution - the further question I would then ask is, how does this revolution ramify into the world of semis?

Is it going to have a major effect on the industry? if so, where will the impact be felt?

Moose

 

[Bernard Murphy]

Thanks all for your answers!

One more question - if we agree that Quantum computing is indeed a sort of revolution - the further question I would then ask is, how does this revolution ramify into the world of semis?

Is it going to have a major effect on the industry? if so, where will the impact be felt?

Moose

I may live to regret this response, but I doubt it. QC and "conventional" semi feel like they are on separate tracks. There may be synergies but not entirely clear since one operates at room temp and the other has to operate at very low temperatures.

 

[smeyer0028]

There is a serious problem with quantum algorithms. Namely, they assume that P is not equal to NP that I think is not true (P!=NP is not proven). Namely that guessing (NP is non deterministic Turing Machines) is faster than calculating using indexing and data structures. The problem is that TMs are very weak machines compared to Von Neumann architecture best modeled by machines call MRAMs (random access memory with unit multiply). All Turing machines are universal but they differ in polynomial computing speed. John Von Neumann understood this is his design of the von Neumann architecture. Here is my paper giving details and references "Philosophical Solution to P=?NP: P is Equal to NP" (reference is arXiv:1603:06018). There are also questions about whether quantum computers can be built. Qbits should really be called Qmultiverses (multi universes from QM theory).