From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/7779 Path: news.gmane.org!not-for-mail From: selinger@mathstat.dal.ca (Peter Selinger) Newsgroups: gmane.science.mathematics.categories Subject: Re: Quipper: a quantum programming language Date: Thu, 20 Jun 2013 16:36:47 -0300 (ADT) Message-ID: References: Reply-To: selinger@mathstat.dal.ca (Peter Selinger) NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit X-Trace: ger.gmane.org 1371761474 22982 80.91.229.3 (20 Jun 2013 20:51:14 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 20 Jun 2013 20:51:14 +0000 (UTC) Cc: categories@mta.ca (Categories List) To: joyal.andre@uqam.ca (=?iso-8859-1?Q?Joyal=2C_Andr=E9?=) Original-X-From: majordomo@mlist.mta.ca Thu Jun 20 22:51:16 2013 Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from smtp3.mta.ca ([138.73.1.186]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Uplp1-0001tF-N4 for gsmc-categories@m.gmane.org; Thu, 20 Jun 2013 22:51:11 +0200 Original-Received: from mlist.mta.ca ([138.73.1.63]:36077) by smtp3.mta.ca with esmtp (Exim 4.80) (envelope-from ) id 1Uplnf-0007Nn-Kb; Thu, 20 Jun 2013 17:49:47 -0300 Original-Received: from majordomo by mlist.mta.ca with local (Exim 4.71) (envelope-from ) id 1Uplnf-0007SD-Tr for categories-list@mlist.mta.ca; Thu, 20 Jun 2013 17:49:47 -0300 In-Reply-To: Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:7779 Archived-At: Dear Andre, the answer, unfortunately, is no. At least we don't think so. We developed this programming language for IARPA, an agency of the U.S. government, and effectively nobody knows whether they have a quantum computer or not. In any case, the language is designed so that it *could* run on a quantum computer, if there was one. So now we are just standing by until somebody builds the hardware :) There is actually one kind of quantum computer that is already on the market: the DWave quantum computer. Unfortunately, our language is not compatible with it; the DWave machine uses a technology called "adiabatic quantum computing", and people are still figuring out how to program it. Our language would be compatible with quantum computers based on the quantum circuit model. Maybe the underlying point of your question is: why would anybody care about a quantum programming language, when there is no quantum computer? One possible answer is: to help figure out how much it would actually cost to build one. It is one thing for a quantum algorithm to appear in a research paper. You will find a lot of statements like "it is well-known that such-and-such can be done in O(n^2) operations", "by applying such-and-such trick this problem can be reduced to another problem with polynomial overhead", and so on. It is quite a different thing to actually program the algorithm, and to worry about how to do so efficiently. The difference between using 10^10 operations or 10^50 operations matters a lot in practice, but not in theory. Moreover, one can then account for additional overhead that people don't usually think about much, like the cost of adding many layers of error correction, physical fail-safe mechanisms, and so on. By coding up some algorithms for "realistic" problem sizes, we get a much better idea of what kind of computing resources this would actually require. ("Realistic" can be defined as the problem size where a hypothetical quantum computer would actually outperform a classical computer running the best known classical algorithm for the problem). Finally, there is some interesting theory that we can discover by considering programming languages for quantum computing. To our surprise, we even found a minor, yet satisfying, application of identity types from type theory. Best wishes, -- Peter Joyal, Andr?? wrote: > > Dear Peter, > > I would like to ask you a naive question: > > Is it runned on an actual quantum computer? > > > Best, > Andr?? > [For admin and other information see: http://www.mta.ca/~cat-dist/ ]