# Quantum Bayesian Networks

## January 31, 2017

### Qubiter and IBM-QASM2 can now communicate via sign language

Filed under: Uncategorized — rrtucci @ 5:15 pm

I’ve always liked mime (Marcel Marceau, Charlie Chaplin,…), physical comedy (using body motions as a source of humor, like Italians do) and the closely related sign-language for the deaf. Sign language can be extremely clever, inventive and expressive. For example, this is how to say Donald Trump in sign-language:

But enough about Trump, who threatens to suck the air and joy out of every conversation. The official purpose of this blog post is to advertise the fact that now Qubiter (https://github.com/artiste-qb-net/qubiter) can convert quantum circuits from its native language to that of IBM, so that you can generate quantum circuits using Qubiter and then run them on the IBM hardware (assuming that those circuits have only 5 qubits and less than about 80 gates)

Recently, the folks at IBM Quantum Experience (IBM-QE) have introduced some very nice enhancements to their QC cloud service. The graphical user interface (GUI) of their website has been revamped. They have also opened two new repositories on GitHub,

Repo 1 introduces their new “intermediate level language” QASM2.0 with a paper in Latex/pdf that teaches the in and outs of their language. This repo also includes samples of qasm2 scripts of two types: some that can be run on their current hardware, and some that can’t be but can still be simulated using their numerical simulator.

Repo 2 gives some Python code for accessing the IBM-QE service via a python script or Jupyter notebook.

To keep up with these IBM enhancements, Qubiter now includes a new file called Qubiter_to_IBMqasm.py This file contains a class of the same name that translates Qubiter “English files” to IBM QASM files. You can write a simple Python script that reads the qasm file produced by the class Qubiter_to_IBMqasm and inputs that string into the code of Repo 2. That way, you don’t even have to visit the IBM-QE website to run your q circuit on their hardware. Alternatively, you can manually copy&paste the qasm file produced by the new Qubiter class into the “QASM Editor” at the IBM-QE website.

The current IBM-QE hardware doesn’t allow all possible CNOTs among its 5 qubits. Out of the 5 qubits 0, 1, …, 4, only qubits 1, 2 and 4 can be physical targets of an elementary CNOT. Also, some pairs of qubits cannot be the two ends of an elementary CNOT because they are physically disconnected. The class Qubiter_to_IBMqasm overcomes both of these limitations. It allows CNOTs among any pair of qubits. Every elementary CNOT that is disallowed is replaced by a compound CNOT; i.e., either 1 or 4 elementary CNOTs (and a bunch of Hadamards) that is equivalent to the original CNOT and is allowed.

## January 20, 2017

### Microsoft Quantum Computing Olympics QIP2017 Comes to A Close Today

Filed under: Uncategorized — rrtucci @ 8:16 pm

Today was an ominous day for the Galaxy. QIP2017 came to a close and Donald Trump was inaugurated as president of the United States…

Today, attendees of QIP2017 got these two postcards with an attached note saying: “Microsoft bids you a fond farewell and would like you to have these 2 commemorative postcards as a final bit of swag to remember QIP2017”

## January 15, 2017

### A photograph of a dangerous thug

Filed under: Uncategorized — rrtucci @ 2:51 am

The purpose of this post is to remind my readers of Microsoft’s thuggish history, as described by the NYT. Will Microsoft be a repeat offender in the emerging field of quantum computing? IMHO, there are some ominous signs that it has started to move full-steam in that direction.

Check out this great article:

MICROSOFT’S WORLD: A special report.; How Software’s Giant Played Hardball Game,By Steve Lohr and John Markoff, New York Times, Oct 8, 1998

Next I will quote the beginning of the article. I recommend that you read the whole thing. The article doesn’t tell the half of it. For example, it doesn’t describe Microsoft’s vigorous attempts to destroy Linux OS and the open software movement. And any company that posed the smallest threat to its Office suite of apps.

In the summer of 1995, a whiff of revolution was in the air in Silicon Valley. The Internet offered a new deal in computing, a fresh opportunity for entrepreneurs to try to break the Microsoft Corporation’s firm grip on the personal computer software business. Leading the challenge was the Netscape Communications Corporation, whose software for browsing the World Wide Web had ignited the Internet boom.

James H. Clark, Netscape’s chairman, spoke boldly of attacking Microsoft head-on. He borrowed imagery from the movie ”Star Wars,” referring to Microsoft as the Death Star and Netscape as the leader of a rebel alliance.

Microsoft answered with a vengeance. It dispatched hundreds of programmers to work on a competing browser and poured many millions of dollars into marketing it. It prodded computer makers and others to distribute its browser, folded the browser into its industry-dominant Windows operating system and gave the browser away free — a campaign intended to ”cut off their air supply,” as a senior Microsoft executive described it.

But it’s not only competitors like Netscape that have encountered Microsoft’s force. Microsoft’s partners, its corporate customers and professional investors who finance new ventures have all collided with it.

A close look at Microsoft’s no-holds-barred push into the Internet software business offers a window into the ways the company uses its market muscle to influence the behavior of virtually every player in the industry.

Some of the cases recounted here figure prominently in the suit brought by the Justice Department and 20 states, scheduled to go to trial later this month, charging that Microsoft at times went too far — and violated antitrust laws.

Regardless of the legal outcome, previously unreported details about incidents in the suit and the other examples provide a more complete picture of Microsoft in action.

*When the Compaq Computer Corporation considered loading Netscape’s browser instead of Microsoft’s on its machines, Microsoft threatened to stop selling its Windows operating system to the big personal computer maker. Compaq, Microsoft’s largest customer in the industry, quickly changed its mind.

*After Spyglass Inc. began supplying Microsoft with its early browser technology, Microsoft announced that it would give away its browser free. The timing came as a rude surprise to its partner Spyglass. The company lost most of its revenues almost overnight, as the technology, which it had also been licensing to companies besides Microsoft, suddenly became available free.

## January 11, 2017

### QIP2017 is next week

Filed under: Uncategorized — rrtucci @ 3:15 am

As I mentioned in my previous post, the QIP2017 conference will be held on Jan 16-20, 2017 at Microsoft HQ, the geometrical center of the DeathStar.

One cannot help noticing that Google, despite it’s considerable commitment to gate model quantum computing, did not sponsor or participate in any committees of Microsoft’s QIP2017. Was this an intentional boycott?

The quantum annealer crowd (DWave, NASA, Lockheed-Martin) has stayed away from QIP2017 too, except for a tiny company called 1Qbit. I do not include Google in that crowd because Google, despite what it seemed to claim when it first hired Martinis, seems to have abandoned quantum annealers to pursue gate model QCs almost exclusively.

All talks at QIP are summaries of papers that have been posted at arXiv months ago, so this conference is an academic version of a pre-scripted American political convention and an ad for MS. If you are not already aware of this, many if not most academic researchers are politicians (some very eager to be bought) first and researchers second. Since the papers have been available to anyone for months, any researcher needing to ask questions to the authors could have done so long ago at almost no cost via email or video conferencing. So it’s hard to justify the cost incurred by the researchers to attend such conventions (entrance fee ~ \$400 + airplane fare + hotel costs, all courtesy of the taxpayer for NSF funded researchers)

Here are some materials that MS is circulating to promote the event. MS intends to use the occasion to show to the world the superiority of the MS race in quantum computing.

## January 6, 2017

### Pythonic Qubiter now has a quantum compiler. The Death Star doesn’t have one yet.

Filed under: Uncategorized — rrtucci @ 12:33 am

As I’ve mentioned many times before in this blog, Henning Dekant (in Toronto) and I (in Boston) founded about a year ago a quantum computer software company called Artiste-qb.net. Our two main products so far are the open source Python programs Quantum Fog and Qubiter. Both programs were originally written in C++, but now they have been rewritten in Python and improved in many ways. This blog post is to announce that the Pythonic version of Qubiter now has a quantum compiler. Hurray for the Rebel Alliance!

Quantum compilers have long been an interest of mine. As far as I know, I was the first one to use the term “quantum compiler” in a paper in the field of quantum computing. I did so in the following 1999 paper

https://arxiv.org/abs/quant-ph/9902062

By a quantum compiler I mean a software program that takes an ARBITRARY unitary matrix as input and decomposes it into a sequence of qubit rotations and CNOTs. In my opinion, quantum compilers that fit this description are useful, even necessary, if one wants to use quantum computers to do artificial intelligence. Because, whereas for most physics applications one can assume unitaries of the form $U = e^{-itH}$ where $H$, the Hamiltonian, has a very special structure, in AI, the unitaries can have an ARBITRARY structure (not known a priori) that doesn’t come from a Hamiltonian with an a priori known structure.

That 1999 paper was the first one to propose using the CS decomposition of Linear Algebra to do quantum compiling. The C++ program Qubiter, which was first released open source simultaneously with the 1999 paper, was the first computer program that used the CS decomposition to do quantum compiling.

Since that 1999 paper, many papers have been written using the same CS decomposition algorithm as my paper, but not citing my work, because, truth be told, dishonesty is rampant among academic researchers.

Other papers have copied the term “quantum compiling” to refer to a task that is related but much less general than what I call quantum compiling, namely, the task of decomposing a single qubit rotation into a sequence of operations from a finite set of gates. The latter task is necessary for fault tolerant quantum computing and was first tackled by Solovay and Kitaev, but they did not refer to it as “quantum compiling”. Nobody did prior to my 1999 paper.

This blog, which is now 8-9 years old, has featured several posts about quantum compilers. These are my favorites:

And now, the latest gossip about quantum compilers.

Up to now, Microsoft’s main and only quantum computer program was Liqui|>, a heavily patented, closed source computer program written in an unpopular language called F#. For many years now, the main writers of Liqui|>, Dave Wecker and Krysta Svore, have been promising to be THE FIRST to provide a quantum compiler, and of course, never mentioning my work. In some papers, KS uses the term quantum compiler to mean the same thing as me, in other papers she uses it to mean software that does the Solovay-Kitaev decomposition. But I can state unequivocally that Liqui|> has no CS decomposition quantum compiler at the present time. So Qubiter is way ahead of them there.

But the plot thickens. Matthias Troyer is a professor at ETH Zurich that works part time, for big bucks, for Microsoft. He has written papers about Liqui|> with Dave Wecker and Krysta Snore. Hence many people were extremely surprised that on Dec. 23, 2016, Matthias and two of his students at ETH Zurich, Minion A and Minion B, released a computer program called ProjectQ that duplicates most of what Liqui|> does and is therefore in direct competition with it. However, ProjectQ is open source, written in Python, and under the Apache License. The suspense is unbearable. Does this mean that Liqui|> will be laid to rest, R.I.P., meaning Dave Wecker’s and Krysta Svore’s work for the last 5 years will be completely ditched? Stay tuned. Microsoft will be holding QIP 2017 on Jan 14-20. That QIP is going to be Microsoft’s 1936 Nazi Olympics, where they intended to dazzle the world with their superiority in quantum computing. Maybe then we will find out, by watching carefully the placement of the people on the main dais during the weapons parade, who is up and who is down.

Henning and I welcome all open source code, even if it is in competition with Qubiter.

IMHO, Qubiter is currently much better than ProjectQ. For one thing, they claim they have a quantum compiler, but they don’t, at least not currently. Not in the sense that I defined it at the beginning of this post. What they do seem to have and call a quantum compiler are some subroutines that expand a single qubit gate with multiple controls attached into a sequence of single qubit rotations and CNOTs. But Qubiter has that already too. Look at its CktExpander.py file.

## Duel Between Microsoft’s ProjectQ and Liqui|> software

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