Quantum Dating Market
By DANIEL DORO FERRANTE • Mar. 9, 2010 @ 18:38 GMT

It’s too late for Valentine’s Day, and too early for April Fool’s Day, so when I first saw the paper a paper titled “Quantum Dating Market, I wasn’t quite sure what to make of it. But in the spirit of William Orem’s post, “Quantum of Love,” I decided to take a look.

It turns out that the paper deals with the well-known “Stable Marriage Problem.” From Wikipedia’s entry on the topic: “Given 'n' men and 'n' women, where each person has ranked all members of the opposite sex with a unique number between '1' and 'n' in order of preference, marry the men and women off such that there are no two people of opposite sex who would both rather have each other than their current partners. If there are no such people, all the marriages are "stable".”

In the quantum dating market paper, O.G. Zabaleta and C.M. Arizmendi use a quantum algorithm to attack the problem rather than the traditional classical algorithm.

To better appreciate this result, you might want to look at some of these sources to better understand the needed ingredients.

Game theory: Wikipedia and Stanford Encyclopedia of Philosophy

Quantum Game Theory: Wikipedia, “An invitation to Quantum Game Theory” and “Quantum Game Theory (AMS Notices)”

Game Theory (classical, non-quantum), roughly speaking, deals with the following problem: situations in which strategical interactions between rational players yields results with respect to the preferences chosen by said players.

Speaking a bit more mathematically, let us define a game with n people (i.e., players) through the following 2 properties,

1. 'n' sets



2. 'n' real-valued functions



The set S_i is called the “Strategy Space” of the i-th player, and the function P_i is called the “Payoff Function” of the i-th player.

This formulation is generic enough to model almost any concrete problem of strategic interactions: the S_i are the available actions to player (we imagine the each player must choose an action); the actions have some consequence and P_i measures what player measures as this consequence.

Given the above, we can try and define what is a “Quantum Game”: naïvely speaking, a quantum game is one in which each player implements a _mixed_ strategy, what requires that the Strategy Space be _expanded_. Thus, in a quantum game, the player can choose a strategy that is a _linear combination_ of the classical strategies,



such that,



However, this linear combination only captures one of the characteristics present in a quantum game: there is still another one which is relevant in this problem: quantum entanglement. Therefore, at the end of the day, the final result of a quantum game is different from what would be obtained through the use of a mixed strategy, once quantum entanglement could lead to very non-trivial results.

In the paper, the authors apply Grover's algorithm, which is a quantum algorithm, to the Stable Marriage Problem. The power of Grover's Algorithm is that it performs an unordered database search in

rather than the classical

Making a loose analogy (a free interpretation of the meaning of a quantum strategy for the dating market), essentially, the paper says that a quantum strategy is more efficient to solve the SMP. Well, this implies that a certain male player would choose to date several female players (with a certain probability to each female player) at the same time, repeating this process several times, until an "equilibrium state" would be found, i.e., until the male player found its "better half".

However, one of the possible outcomes of the quantum entanglement would be that in which all female players decide, at the _same time_, not to date the male player anymore. So perhaps not such a good romantic outcome after all.


Free Radical
By WILLIAM OREM • Feb. 15, 2010 @ 04:02 GMT



An appreciative farewell is due this month to a true scientific radical. While he wasn’t a member of FQXi, his enthusiasm for deep cosmological questions, coupled with an absolute willingness to disagree openly – even vociferously! -- with the entire tide of conventional thought marked him as a rare and courageous thinker.

I’m speaking, of course, of Geoffrey Burbidge, grand old man of the alternative astrophysical community, Bruce Medalist, and almost the last remaining bugbear of the Standard Cosmological Model. Burbidge died this month at age 84, having revolutionized the field by first introducing (along with E. Margaret Burbidge, William Fowler, and Fred Hoyle) the notion of stellar nucleosynthesis in 1957. The team laid out the process in one of the great papers of the century, casually known to this day as B²FH. Thanks to B²FH, we understand where the heavy elements came from (contrary to earlier speculation, the Bang produced only hydrogen, helium, and lithium; lovely in their simplicity, but not much more than a primal haze). Burbidge and his coworkers presented compelling evidence that the stars, going through their cycles of life and death, crushed these light elements into more complex forms to be blasted out into space during supernovae. The earth and all its inhabitants, including the one writing this memorial, are evolution’s handiwork on the remnants of exploded stars.

Burbidge called me at home a few years back after I had written an article on his dogged opposition to the SCM. At the time I was science editor on a local paper; we had conversed by phone a few times during the writing of the piece, and then I had gone on to other things. I wasn’t sure why he was phoning me, but after several minutes realized he was simply keeping the conversation going – a charming aspect of his personality I would later learn was a commonplace among those who interacted with him. On that last call we talked for about a half hour about the “Quasi-steady State” model, his theory that the cosmos is infinitely old, experiencing partial collapses and expansions but no singularity. Perhaps most radical of all, Burbidge was skeptical of red-shift data altogether, which is, as they say, kicking at the big pole of the tent.

The man had a fascinating mind. Are we too quick to assume quasars are “cosmologically distant,” and should we (as Halton Arp maintains) take a closer look at their curious visual proximity to active galactic nuclei? Were people in the West more ready to accept the Bang than a steady-state model because the dominant religion had cued them to believe the universe has a beginning in time? Burbidge had even written his own alternative textbook, along with Hoyle and J. V. Narlikar, taking back the SCM and interpreting the data that led to it in an entirely new light.

The net is full of nonsense; everybody knows that. There are as many self-proclaimed geniuses touting a radical cosmology as there are gurus trying to conflate science with superstition. What I admire most about Burbidge, though, is the fact that for all his plying of strange waters he never let go of the rigorous standards of evidence required of credible theorizing. Was he right about SCM? Not many think so, especially after COBE and WMAP. I don’t think so myself. But ninety-nine can be wrong; I am reminded of the 1931 pamphlet “100 Scientists Against Einstein.” Burbidge’s role as gadfly reminds us of how uncertain we actually are of the correct way to read our data; the danger of merely following the crowd; of writing our cultural expectations into nature; and -- exactly because of that -- the necessity of holding on to the steady rudder of objective experiment. Look again: what today thinks it knows may well become the luminiferous aether of tomorrow.




Bowling with the CMB
By MARK WYMAN • Feb. 7, 2010 @ 19:54 GMT

A new WMAP data and paper release is always a little Christmas for cosmologists. Among the latest set of papers based on seven years of operation, released last month, one concerning whether there are any Cosmic Microwave Background Anomalies suggests that the WMAP team has an affinity for bowling. Why? Because they set ‘em up... and then the knock ‘em down.

A bit of background: The WMAP dataset contains the finest map we yet have of oldest primordial light in existence -- the first photons released after the Big Bang that were able to make it all the way to us, living over 13 billion years later. As a result, to say that people have pored over these data with tremendous care and effort is to understate the case.

The simplest models for the early Universe in the dominant inflationary paradigm predict that the fluctuations in the temperature of the light from the CMB will be well described by a Gaussian random field. Thus, one of the most intriguing things to look for in the data are deviations from pure Gaussianity, which would signal that something extra and interesting was going on in the early Universe. This can be exciting, but comes with a critical caveat: statistics can be an unfaithful friend to the eager data-miner. This is because a purely random field on which 100 tests are done will, on average, produce at least one result that is only 1% probable in the underlying model. Hence, any anomaly that is found in the data must be provably much rarer than any random fluctuation if one is to believe that it is truly a deviation from the theory.

Given human nature and the hopes of glory that rest in each of our hearts, perhaps what happened was inevitable. As time passed, various experts on the WMAP data began to uncover strange anomalies in those data that appeared, upon investigation, to be just the sort of rarer-than-random things that would be the mark of a real discovery: Right away, people noticed that there was an huge cold spot smack dab in the middle of the map. Then the map seemed not to have enough structure on the largest scales (in technical terms, it had anomalously low power in its quadrupole, and seems to lack sufficient correlation on wide angular scales) Then the quadrupole was found to align with the octupole, defining a special direction in space that was cleverly named by one of its earliest investigators as the “axis of evil.” And then two halves of the sky were found to have starkly differing levels of small-scale temperature correlation, a so-called power asymmetry.

It’s critical to note that these anomaly-discovering experts never included members of the actual WMAP team. The team was itself admirably impartial throughout the hoopla that attended each discovery, presumably well aware that approval from the team would be tantamount to a final verdict on the discovery and that dismissal without careful analysis would be irresponsible. Nonetheless, they have clearly been keeping close watch on these developments. This new paper is their long-gestated answer to all these claims.

In short, their result is negative: they don’t believe the anomalies are real. They reach this conclusion through a careful study of each one separately. First, they give a concise review of each anomaly and the opposing arguments regarding its significance. This gives the paper an almost Thomistic style; by the middle, I was half expecting a sed contra to pop up. Then, they improve and deepen the original analysis, taking into account other developments in the literature. In each case but one, they conclude that the anomaly is less statistically significant than it at first seemed, moving each out of the “rarer-than-random” column and onto the “almost certainly just a fluke” side of the ledger.

I’m sure you’re curious now to know what the last anomaly standing is. It’s a bit of a curious and technical one: a quadrupolar “effect” in the two-point power spectrum. That is, the way the temperatures of the map are correlated depends a bit on where they are located on the sky, in a pattern that has four distinct quadrants. However, before you start writing your paper on the asymmetric Universe, it turns out that even this Official WMAP Approved anomaly probably isn’t exciting evidence for new early Universe physics. The critical evidence disfavoring an early Universe origin is that the effect isn’t equally present in different frequency bands, which true CMB effects must be; and the preferred direction that the effect aligns is suspiciously similar to the ecliptic pole -- the direction in the sky picked out by our (and the WMAP satellite’s) orbit around the sun.

All of which is very reasonable and proper, and a bit disappointing. I, like anyone, am always eager for the Universe to throw us a little loop, to find a bit of an Easter egg left from the Universe’s earliest days. But as the WMAP team points out in their conclusion, we humans are simply hardwired to discern patterns, so much so that we do it too well -- finding patterns where none really are. Their example, a fun tidbit with which I’ll close, is pointing out the appearance of the initials “S. H.” in the map, which is certainly (?) not evidence for new physics, unless Stephen Hawking has something very surprising up his sleeve.


Astrotheology: Do Aliens Have Their Own Jesus? Are Aliens Sinless?
By ZEEYA MERALI • Jan. 27, 2010 @ 15:43 GMT

Yesterday I attended a meeting at the Royal Society in London about how the discovery of extra-terrestrial intelligence would affect people and society, and was introduced to a whole new discipline: astrotheology. A big talking point at the meeting (stated somewhat crudely) was whether the discovery of alien intelligence would throw religion into crisis. (Thank you to Mike Croft for his rejoinder yesterday: “That’s a very poor question. Would science be in crisis if God was discovered?”)

My first thought was, “No, why should religion crumble just because aliens were discovered?” and I was slightly surprised (perhaps naively) that apparently the opposite view is more widely held. But according to Ted Peters, a Christian theologian (who now also dabbles in astrotheology, pondering whether meeting our space neighbours could throw humanity into an existential crisis) the issue is partly based on the unspoken assumption that religion is primitive and inferior, while science is superior. Should aliens make contact with us, one would assume they are more technologically advanced than we are, and hence—the argument goes—more highly evolved, to such an extent that they will in fact have “evolved beyond religion.” (I will come back to this point later.) What would primitive earthlings do when faced with their more evolved scientific superiors?

To address whether religious people really do feel that their beliefs would be threatened by contact, Peters has conducted a survey of people from various faiths to check the hypothesis that “upon confirmation of contact between earth and an extraterrestrial civilization of intelligent beings, the long established religious traditions of earth would confront a crisis of belief and perhaps even collapse.” New Scientist has covered his findings in detail, so I will direct you there for the stats rather than typing them all out myself. But the upshot—not very surprising to many of faith—is that Roman Catholics, mainline Protestants, evangelical Protestants, Orthodox Christians, Mormons, Jews, and Buddhists really aren’t too worried by the prospect that the universe contains other intelligent beings. Anecdotal evidence from Muslims and Hindus suggest they feel much the same way. Most disagreed that the discovery would shake their personal faith and many believe that others who share their own faith would also take alien contact in their stride. (Some suggest it would even strengthen their faith and provide evidence for the existence of nonhuman intelligent beings described in sacred texts.)

So where does the notion that religion will crumble in the face of contact come from? Well, that was also partially addressed in the survey. Respondents tended to assume that while those following their own religion (or non-religion, in the case of non-affiliates and atheists) wouldn’t be too shaken, _other_ religions would be. “So those other people would have the problems!” says Peters.

Question answered then: Religion will not crumble. Or perhaps it’s not that simple? FQXi’s Paul Davies asked rather cuttingly in response to the survey, “how many people have an understanding of their own religion?” While he agreed that most religions could incorporate aliens into their worldview with little difficulty, he argued that for Christians there should be a serious problem: “Can you really be a Christian and not believe that Jesus was the incarnation of God who came to save a particular species?”

Peters responded that he has also looked into the views of many Christian theologians, and there opinion differs. Some believe that there could be only one incarnation—species-specific to humans. Others allow for multiple incarnations, with other alien species (or animals on Earth) having their own “Jesus.”

To complicate matters further, it’s also not clear that Christians _should_ believe that extra-terrestrials even need saving. Peters described how C. S. Lewis once speculated that aliens may never have gone through the fall, that is, no alien Adam and Eve were tempted to eat of the forbidden fruit (or the alien equivalent), and hence aliens do not need saving by a Christ-like figure. I am aware that I am straying into areas of Christian theology (let alone areas of alien Christian theology) that I am not an expert on, so I should maybe open the floor to people who know more than me here.

But, if that is the case, then a sinless alien race could be out there waiting to...inspire us? (Altruistic alien missionaries coming to Earth may not be a good thing either.) Which brings me back to the initial assumption that any advanced alien race should have evolved beyond religion. That may be the case. Or they may provide an example of a more spiritual way to live. In either case, how would their discovery affect you (whether you are an atheist, a religious person, undecided, or unwilling to declare)? Will it diminish your sense of human dignity if we meet beings that are more advanced than us? Should it?

While you’re pondering those questions, I’ll leave you with Jon Chase’s astrobiology rap, which was performed live for us at the meeting.




What is Ultimately Possible in Physics: Contest Results Announced!
By ANTHONY AGUIRRE • Jan. 19, 2010 @ 19:02 GMT

FQXi is pleased to announce the winners in our Essay Competition, "What Is Ultimately Possible In Physics?" The Review Panel worked hard through the holidays debating the finalists. After lengthy discussions, they turned in their ratings, which we then combined with the original Community ratings to determine the final results.

The full list of winners and links to their essays can be found here. First Prize goes to: "Stardrives and Spinoza" By Louis Crane. In his essay, Louis examined a piece of far-out technology that might just be possible in the future: the construction of artificial black holes for use as power sources, and the potential side effect of creating new life! The essay touches on technical and theoretical issues, as well as the ethical and 'spiritual' implications. Judges praised this well-rounded essay for its insightful content, for tackling many different interpretations of the essay question, and for just being fun to read.

Second Prizes, including $5,000 and Membership in FQXi, goes to: "On the impossibility of superluminal travel: the warp drive lesson" By Carlos Barcelo, Stefano Finazzi & Stefano Liberati; and "At the Frontier of Knowledge" By Sabine Hossenfelder.

The essay of Carlos, Stefano F. and Stefano L. discussed a piece of physics that first sounds implausible, then maybe possible, and then maybe not after all. Judges praised the essay for a rigorous discussion of an interesting topic, with an overview of old material and new speculations.

The essay of Sabine attacks our presumption that anyone could answer the essay question, arguing that we can never know if we have hit a limit of scientific knowledge. Judges praised the witty and logical style and the author's creative questioning of the question.

A further six essays received Third Prize, splitting the $10,000 pot evenly, and ten more received Fourth Prize and $1,000. (Again, full results are at here.) The Panel did not choose to award further Special Commendations, since it felt its views were still expressed well enough by the final results.

The Panel's ratings had a strong effect on the results, since the ratings at the time of the Finalist cut were so tight, and because each Panelist was given the weight of 3.0 normal Community voters. This meant that there were considerable differences between the rankings at the cut and the final standings. Some essays that were front runners after the cut did not win prizes, and some that were not in the top twenty finished in the top ten. The final ratings were still close, though, with over ten essays missing Fourth Prize by a half point or less.

It's agreed by many of the entrants, readers, and the panel that this was a hard question to answer (c.f. Sabine), and hence a hard contest to judge. The panel expressed a variety of opinions on all the essays, and even the highest rated were not unanimously praised. We should all keep in mind that the awarding of a prize signifies that the winner is a relevant and interesting essay: something that is well written, thought provoking, stimulating, fun, etc. It should not be construed to mean that everyone, including the members of the panel, believe that the approach is complete, flawless, unobjectionable etc.!

On the flip side, failure to win a prize should not be construed as indicating that there is something fundamentally wrong with an essay; lots of essays that were very well liked by at least some panelists ended up off the list. Moreover, the Panel judges had a hard time knowing how to deal with differing levels of technical sophistication. Some of the essays, including a few of the winners, have a lot of equations and other technical material. The Panel members disagreed strongly on the readability of such essays and even the importance of readability. This situation shows us that for the next contest, we the organizers should be very clear about the expected level of sophistication.

After what we've said here, we won't release additional information on the Review Panel's work, such as who the judges were, what their reviews said, what the rankings within the tiers were, etc. The important information is who won what prize, and anything else will detract from that.

And far more important, we think, than who won what prize is the prime purpose of the contest: generating interesting material and lots of discussion!

On behalf of all the FQXi administration, we say thank you to all the participants. It's been exciting to see the depth and range of ideas that have come out, and gratifying to see how supportive and interactive the community has been amongst itself. We've had fun and learned some things, and I hope you all have, too.

Looking forward to the next contest question,

Anthony & Brendan

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