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VW Solves Quantum Chemistry Problems on a D-Wave Machine

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Re: VW Solves Quantum Chemistry Problems on a D-Wave Machine

#41

Post by chaboud »

AlexCoventry wrote: post #15

What's the business motivation of this research, for VW?

1) Lithium Hydride? That's battery chemistry right there.

2) Marketing buzz from being seen as a forward thinking research company instead of a place that engineers their way out of costly regulatory compliance.

Given that this came from their SF group, it seems like a low-cost high-buzz exercise, and, if it had worked out, they might have some interesting methodologies for chemistry/structural improvement.

It seems like a win-win-win thing to me.

Re: VW Solves Quantum Chemistry Problems on a D-Wave Machine

#42

Post by jhayward »

B1FF_PSUVM wrote: post #23
pas wrote: post #17

Earlier quoted context omitted.

Batteries? Fuel efficiency? Better catalytic emission filter?

Better cheating? Although they're already pretty successful at that, the dieselgate thing cost them some money, but none of the executives in charge of the fraud is in jail or financially punished. ["How VW Paid $25 Billion for 'Dieselgate' – and Got Off Easy" - https://en.wikipedia.org/wiki/Volkswagen_emissions_scandal ]

> none of the executives in charge of the fraud is in jail or financially punished.

This is nothing relevant to the article, it's just ad-hominem attacks, and factually incorrect at that.

The very wiki page you cite says that CEO Winterkorn is charged with fraud, the CEO of Audi has been arrested, and 6 executives in the US are presently under charges.

Re: VW Solves Quantum Chemistry Problems on a D-Wave Machine

#43

Post by archgoon »

empath75 wrote: post #32
Havoc wrote: post #2

>For beginners, he says, an actual D-Wave device isn’t even necessary. I find this somewhat surprising. If you think of AI code designed for GPUs, there I can see "yeah you can practice on a CPU". It'll suck but it'll work. For quantum tech the entire sales pitch is that it's fundamentally different...doing what's near impossible on conventional hardware. Yes I realise he's talking about the library so annealing on a…

Everything I’ve read says that the d-wave isn’t a real quantum computer.

This is basically correct.

When people talk about "Quantum Computers" that can factor large primes, they are referring to a Universal Gate Quantum Computer. As of today, the largest Universal Gate Quantum Computer has 72 qubits.

The DWave Quantum Annealers are essentially a special purpose device that performs Quantum Annealing. What they refer to as 'Qubits' are very different from the entangled Qubits of a Universal Quantum Computer. To the best of my knowledge (and the paper explicitly distinguishes between the two types), it has yet to be demonstrated that Quantum Annealing is equivalent to Universal Gate Quantum Computer (and is generally suspected not to be), is in it's own complexity class, or even if it provides any complexity speedup over classical computers.

Re: VW Solves Quantum Chemistry Problems on a D-Wave Machine

#44

Post by garmaine »

stochastic_monk wrote: post #22
FeepingCreature wrote: post #16

Earlier quoted context omitted.

For the record, the concept is called Quantum Supremacy [1]. So far, there is no demonstration of quantum supremacy, but it seems like it may just be a matter of time. [1] https://en.wikipedia.org/wiki/Quantum_supremacy

It’s related, but quantum supremacy is about asymptotic speedups rather than actual speed differences. Additionally, it’s worth keeping in mind that D-Wave machines aren’t true quantum computers in the sense that they can’t perform Grover’s or Shor’s algorithms.

It’s not clear what “true quantum computer” means. There are many different types of quantum computers, and quantum annealing, what D-wave does, is one. It’s just the least interesting of the bunch...

Re: VW Solves Quantum Chemistry Problems on a D-Wave Machine

#45

Post by philipkglass »

sampo wrote: post #26

> The researchers did not run a similar algorithm on a conventional computer system to see whether the D-Wave computation was faster.

Standard quantum chemical methods for this sort of problem would finish in a fraction of a second on a Raspberry Pi. Calculating the ground state energy of a tiny system like LiH was tractable way back in the 1960s. I'd need to see their actual numbers to determine when a conventional computer first reached their level of accuracy on LiH but I'm sure it is several decades back.

EDIT: according to the paper, the initial energy at each point was found using the Hartree-Fock method with a minimal STO-3G basis set. This is one of the simplest and oldest approaches to this sort of calculation on a conventional computer. For these starting calculations they used Psi4 [1] by way of OpenFermion [2]. For the H2 molecule, their additional DWave calculations improved the accuracy of the distance-energy curve over the baseline Hartree-Fock/STO-3G calculations. For LiH, there was no improvement (Figure 3). The total runtime of their approach was therefore that of the conventional approach plus an additional series of calculations that did not yield improvements in the case of LiH.

[1] http://www.psicode.org/

[2] https://github.com/quantumlib/OpenFermion

Re: VW Solves Quantum Chemistry Problems on a D-Wave Machine

#46

Post by garmaine »

archgoon wrote: post #43
empath75 wrote: post #32

Earlier quoted context omitted.

Everything I’ve read says that the d-wave isn’t a real quantum computer.

This is basically correct. When people talk about "Quantum Computers" that can factor large primes, they are referring to a Universal Gate Quantum Computer. As of today, the largest Universal Gate Quantum Computer has 72 qubits. The DWave Quantum Annealers are essentially a special purpose device that performs Quantum Annealing. What they refer to as 'Qubits' are very different from the entangled Qubits of a Universa…

There isn’t a universal quantum computer in the sense that there is a universal Turing machine for classical computation. All quantum computers are special purpose circuits, not general logic machines.

Re: VW Solves Quantum Chemistry Problems on a D-Wave Machine

#47

Post by [deleted] »

KKKKkkkk1 wrote: post #40
twtw wrote: post #21

Earlier quoted context omitted.

Right, and the paper itself is very upfront about that. I don't have any objection to the research, which is likely very valuable, but I do find it strange that the article claims they solved two problems without mentioning that only one of the solutions was correct. It would be great if the article said they solved one and made good progress on techniques for the second that will likely work on next generation hardw…

> It's like the U.S. national labs unveiling the world's first exaflop supercomputer, with a footnote indicating that in fact the computer is only 100 petaflops at the moment. Can you add context?

[deleted]

Re: VW Solves Quantum Chemistry Problems on a D-Wave Machine

#49

Post by [deleted] »

garmaine wrote: post #46
archgoon wrote: post #43

Earlier quoted context omitted.

This is basically correct. When people talk about "Quantum Computers" that can factor large primes, they are referring to a Universal Gate Quantum Computer. As of today, the largest Universal Gate Quantum Computer has 72 qubits. The DWave Quantum Annealers are essentially a special purpose device that performs Quantum Annealing. What they refer to as 'Qubits' are very different from the entangled Qubits of a Universa…

There isn’t a universal quantum computer in the sense that there is a universal Turing machine for classical computation. All quantum computers are special purpose circuits, not general logic machines.

[deleted]

Re: VW Solves Quantum Chemistry Problems on a D-Wave Machine

#50

Post by jcranmer »

KKKKkkkk1 wrote: post #40
twtw wrote: post #21

Earlier quoted context omitted.

Right, and the paper itself is very upfront about that. I don't have any objection to the research, which is likely very valuable, but I do find it strange that the article claims they solved two problems without mentioning that only one of the solutions was correct. It would be great if the article said they solved one and made good progress on techniques for the second that will likely work on next generation hardw…

> It's like the U.S. national labs unveiling the world's first exaflop supercomputer, with a footnote indicating that in fact the computer is only 100 petaflops at the moment. Can you add context?

This is referring to the Summit supercomputer announcement a few months ago.

Measuring the speed of a supercomputer is difficult because there are several factors that control performance that affect benchmarks very differently. The most common benchmark in use is LINPACK, which measures how long it takes the computer to solve an appropriately large matrix equation Ax = b and then computes how many floating-point operations such an equation notionally takes. This has been criticized for various reasons, but it's what TOP500 measures.

Summit scored 143 PFLOPS on this metric. However, the press release called it a exascale supercomputer because it can issue 1 quadrillion instructions per second, so 1 exaop. To most people in the industry, the goal of exascale meant 1 EFLOP on LINPACK, so it really does come across as saying "We built a 1 EFLOP computer (footnote: only 143 PFLOPS)."

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