Quantum Bayesian Networks

March 31, 2016

MIT Stunned by Scalable Quantum Computer

Filed under: Uncategorized — rrtucci @ 11:16 pm

Okay, I don’t expect any of my readers to believe me, but I have a Martian WiFi wormhole connection which allows me to access the Internet in the future. Today, I came upon this article that will be published exactly 15 years in the future.


MIT Stunned by Scalable Quantum Computer
April 1, 2031. MIT Tech Review

A team of scientists from MIT led by Prof. (also Dean of MIT Physics Dept., and chief editor of Physical Review) Isaac Chuang has just published a paper in Physical Review that describes how they used a 5 qubit quantum computer built of superconductive Niobium rings called SQUIDs to show that 15 =3×5.

Those of us who are old enough to remember may recall that MIT was the first to show in 2001 that 15=3×5 with an NMR quantum computer.

Then, MIT scientists stunned themselves with their brilliance once again when 15 years later, in 2016, they were the first to show 15=3×5 with an ion trap quantum computer.

And now, 15 years later, in 2031, MIT scientists were stunned once again, as if by a lightning out of the blue, when they managed against all odds to show that 15=3×5 with a superconductive quantum computer.

All 3 times that MIT has shown that 15=3×5, they have claimed that their device is scalable. We are beginning to believe them, but then again, in 2031, we are now so old that some days we can’t readily recall the current US president’s name.

Back in 2016, when Prof. Chuang was asked why he wasn’t comparing his ion-trap device to those of David Wineland’s team (at NIST, Colorado), and Chris Monroe’s team (at U. Of Maryland), Prof. Chuang pointed out that those people’s devices were so different to his that he was totally unaware of their existence. According to Prof. Chuang, his device was placed in a lab-room with green colored walls, whereas Wineland and Monroe had used beige colored walls. According to a powerful theorem by Prof. John Preskill of Caltech, the boundary conditions (in this case the color of the lab-room walls) affects so much the evolution of the bulk (in this case the device), that quantum devices placed in lab-rooms with green and beige colored walls behave so differently that they are incomparable. Or so Chuang claims.

Today, April 1, 2031, Prof. Chuang was asked why he isn’t comparing his 5 qubit superconductive device to the 100 qubit superconductive devices built by Google and IBM last year. Once again, Prof. Chuang defers to Preskill’s Theorem which proves those devices are incomparable to his.

Prof. Chuang delivers Commencement speech at MIT

Prof. Chuang delivers Commencement speech at MIT

Coed hen at MIT 2031 graduation ceremonies very impressed by Prof. Chuang's piercing pronouncments

Coed hen at MIT 2031 graduation ceremonies very impressed by Prof. Chuang’s pronouncements

March 29, 2016

Qubiter on the brink of doing Quantum Chemistry

Filed under: Uncategorized — rrtucci @ 6:35 pm

On behalf of the artiste-qb.net company, I am pleased to announce that Qubiter now has a new class called PhaseEstSEO_writer.py that endows it with the superpower of being able to generate and simulate quantum circuits for quantum phase estimation.

The quantum Phase Estimation circuit (PEC) was invented in 1995 by Kitaev. Since then, it has found many applications in quantum computing. Microsoft Liqui|>, the main competitor of Qubiter, uses PEC to find the ground state of molecules.

In fact, Liqui|> can generate many other circuits besides PEC, but most of them are not very commercially viable. For example, Liqui|> can generate quantum error correction circuits, but error correction will most likely be done by the hardware manufacturers, so QC programmers won’t need to implement it via Liqui|> in their circuits. Liqui|> also does Shor’s algo, but I don’t think Shor’s algo will be a big money maker, because it requires thousands of qubits, so it will be one of the last applications to be implemented on a QC. By the time it is implemented, post quantum crypto, which is impervious to it, will have been in general use for many years.

So most of the circuits that Liqui|> can generate & simulate will never be commercially viable, but those for doing quantum chemistry probably will be.

The Liqui|> team claims to have used experimentation with Liqui|> to reduce by a factor of a thousand the size of their QC circuit for finding the ground state of molecules with PEC. They claim that their new, optimized circuit will give an answer in an hour of running on a gate model QC, once those beasts arrive. Such calculations would take billions of years for a classical computer to perform, they claim.

The Liqui|> authors like Krysta Svore seem well aware that Quantum Chemistry is one of the most commercially viable and potentially lucrative applications of Liqui|>. You can almost see the dollar signs in their beady eyes when they speak about quantum chemistry.

But Qubiter is throwing a spanner into their nefarious plans.

Microsoft Liqui|> is closed source and heavily patented. Also, it is written in a very unpopular language F#. Qubiter, on the other hand, is open source and written in the super popular language Python.

And now Qubiter allows everyone, not just Microsoft egg heads, to do QC quantum chemistry too.

March 22, 2016

First version of Qubiter (a quantum computer simulator) is out. It says: “Welcome, my navigator. Where do you want me to take you next?”

Filed under: Uncategorized — rrtucci @ 4:44 pm

artiste-qb.net has just uploaded at GitHub its first version of Qubiter, a quantum computer simulator, under the BSD license and written in Python.

It’s saying to you: “Welcome, Navigator. Where do you want me to take you next?”



Over the last 20 years, dozens of quantum computer simulators (for gate model, aka quantum circuit QC) have been released. Here is a partial list. So what makes this one special?

Let me compare Qubiter with Microsoft’s very famous quantum simulator called Liqui|>.

  • Liqui|> is closed source (and heavily patented), Qubiter is open source under BSD license
  • Liqui|> is written in F#, Qubiter is written in Python. User base of Python is ~ 100 times bigger than that of F#. And believe me, programmers are very savvy consumers of programming languages.
  • Dave Wecker (rhymes with wrecker), chief architect of Liqui|> , has been quoted as saying that he estimates Liqui|> has about 30,000 lines of code. Qubiter currently has less than a 1000, and does all the basics and much more. So tell me, what would you prefer to have to grok, 30,000 or 1,000 lines of code?

I hope you enjoy it. Or as my grandma used to say,

Stai zitto e mangia!!

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