{"id":2673,"date":"2010-01-21T12:12:49","date_gmt":"2010-01-21T17:12:49","guid":{"rendered":"http:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=2673"},"modified":"2010-01-27T20:03:14","modified_gmt":"2010-01-28T01:03:14","slug":"various-and-sundry-11","status":"publish","type":"post","link":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=2673","title":{"rendered":"Various and Sundry"},"content":{"rendered":"
  • The latest New Scientist has an article<\/a> about Erik Verlinde’s “entropic gravity”<\/a>, with enthusiastic remarks from Robbert Dijkgraaf and Stanley Deser. Gerard ‘t Hooft expresses pleasure at seeing a string theorist talking about “real physical concepts like mass and force, not just fancy abstract mathematics”. According to the article, the problem with Einstein’s General Relativity is that its “laws are only mathematical descriptions.” I guess a precise mathematical expression of a theory is somehow undesirable, much better to have a vague description in English about how it’s all due to some mysterious entropy. There’s even an editorial<\/a> about this:
    \n

    Now we could be closing in on an explanation of where gravity comes from: it might be an emergent property of the way objects are organised, much as fluidity arises as a property of water…. This idea might seem exotic now, but to kids of the future it might be as familiar as apples.<\/p><\/blockquote>\n

    In a new preprint<\/a>, Lee Smolin uses Verlinde’s work in a very different way, to show that Newton’s law of gravity must emerge from the microscopic quantum gravity approach Smolin favors, that of loop quantum gravity.<\/li>\n

  • Also on the New Scientist\/entropy front, there’s a review<\/a> by Craig Callender of Sean Carroll’s new book. I’d been wondering what philosophers of science would have to say about the book, and the reaction to Carroll’s multiverse explanation of the arrow of time was about what I suspected it would be:
    \n

    Daring to speculate in the absence of well-confirmed theory, Carroll jumps from clue to clue, from black hole physics to string theory to the holographic principle, until he arrives at his destination: an eternal “mother space-time” from which a multiverse of baby universes are continually bubbling up and pinching off. The mother space-time is a high entropy vacuum that gives birth to universes like our own, some of which we can expect to begin with low entropy. Problem solved, says Carroll, because that is natural.<\/p>\n

    Carroll seems slightly embarrassed by the many leaps of faith he asks of his reader in proposing this solution, and the prose of Part IV sometimes reads like the pitch of an honest used-car salesman: “This car is a dream! True, the tyres are bald, brakes unsound and transmission sticky, but you’ll love it!”<\/p>\n

    Carroll and other peddlers of multiverses make us an offer: we will explain the unexplained if you add vast unconfirmable matters of fact into your ontology. In this case that includes a host of disconnected baby universes, an eternal mother universe entirely unlike ours, and half a dozen unknown mechanisms to get all this working. Assuming this explains the low entropy past – and with so much unknown it is hard to be sure another conspiracy isn’t lurking within – is this a good deal?<\/p>\n

    In most cases I don’t think so. Why is Manchester United perennially a good soccer team? Surely most solutions of the laws of physics don’t have them winning so much. How unnatural (and unfair) those initial conditions are! Nonetheless, a frothy sea of baby universes tempts no one. We shrug and say, that’s just the way it is. Sometimes it is best not to scratch explanatory itches.<\/p><\/blockquote>\n<\/li>\n

  • Witten now has a long preprint<\/a> out about his beautiful recent work on analytic continuation of Chern-Simons theory that I wrote about here<\/a> last fall.<\/li>\n
  • My colleague Johan de Jong has been working for a few years now on what he calls the Stacks Project<\/a>, which aims at a detailed, foundational exposition of the theory of algebraic stacks, beginning with the necessary algebraic geometry. He has structured this along the lines of an open source software project, encouraging contributions to the project from other algebraic geometers. The latest addition to the project is a blog<\/a>.<\/li>\n
  • The filmmakers who brought us What the Bleep Do We Know?<\/a> have recently completed a new film, entitled Ghetto Physics: Will the Real Pimps and Ho’s Please Stand Up!<\/a>. According to Cornel West “This intelligent and intelligible film is a must-see for all of us.” There may be a theatrical release this year.<\/li>\n
  • A huge proportion of the mathematics research literature is now controlled by the publishing company Springer Science + Business Media. Last April there were reports<\/a> that the owners of the business had it up for sale for about $2.9 billion. The CEO denied these reports, stating “We are not for sale, there is no truth in Springer being sold”. Last month came the announcement<\/a> that Springer was being sold, to two private equity firms from Sweden and Singapore. The price was about $3.4 billion, with the new owners also taking on $2.9 billion of the company’s debt.\n

    It’s not clear if there are any implications for mathematics publishing, with this perhaps just a transfer of control of the mathematics literature from one group of private equity firms to another.<\/li>\n

  • In the next couple months Princeton University Press will publish a short new popular book on string theory, Steve Gubser’s The Little Book of String Theory<\/a>. It is only 184 pages long and appears to be somewhat similar to efforts like The Complete Idiot’s Guide to String Theory<\/a>, String Theory Demystified<\/a>, and String Theory for Dummies<\/a>, but less technical, with less graphics, and a lot shorter.\n

    According to the promotional material, the author<\/p>\n

    describes efforts to link string theory to experimental physics and uses analogies that nonscientists can understand. How does Chopin’s Fantasie-Impromptu relate to quantum mechanics? What would it be like to fall into a black hole? Why is dancing a waltz similar to contemplating a string duality?<\/p><\/blockquote>\n

    and<\/p>\n

    After reading this book, you’ll be able to draw your own conclusions about string theory.<\/p><\/blockquote>\n

    The introduction is available here<\/a>, and ends with this description of recent debates over string theory:<\/p>\n

    I don\u2019t aim to settle any debates about string theory in this book, but I\u2019ll go so far as to say that I think a lot of the disagreement is about points of view. When a noteworthy result comes out of string theory, a proponent of the theory might say, \u201cThat was fantastic! But it would be so much better if only we could do thus-and-such.\u201d At the same time, a critic might say, \u201cThat was pathetic! if only they had done thus-and-such, i might be impressed.\u201d in the end, the proponents and the critics (at least, the more serious and informed members of each camp) are not that far apart on matters of substance. everyone agrees that there are some deep mysteries in fundamental physics. nearly everyone agrees that string theorists have mounted serious attempts to solve them. And surely it can be agreed that much of string theory\u2019s promise has yet to be delivered upon.<\/p><\/blockquote>\n<\/li>\n

  • For two wonderful but very different short memoirs by mathematicians about aspects of their research work, see William Stein’s Mathematical Software and Me: A Very Personal Recollection<\/a>, and Michael Harris’s A Mathematical Dream and Its Interpretation<\/a>.<\/li>\n

    Update<\/strong>: The Onion carries the news that World Physicists Complete Study of Physics<\/a>. The quote from a physicist is:<\/p>\n

    Yeah, that about does it for physics. All done. Math can pretty much take it from here.<\/p><\/blockquote>\n

    Update<\/strong>: Robert Helling gives his take on the Verlinde paper here<\/a>. It reminds him of a certain proof that reaches an unreasonable conclusion using the rules “time=money” and “money is the root of evil”. I noticed this via an arXiv trackback. Funny, for some reason there are no trackbacks to my postings on this topic<\/p>\n","protected":false},"excerpt":{"rendered":"

    The latest New Scientist has an article about Erik Verlinde’s “entropic gravity”, with enthusiastic remarks from Robbert Dijkgraaf and Stanley Deser. Gerard ‘t Hooft expresses pleasure at seeing a string theorist talking about “real physical concepts like mass and force, … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-2673","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2673","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2673"}],"version-history":[{"count":13,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2673\/revisions"}],"predecessor-version":[{"id":2683,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2673\/revisions\/2683"}],"wp:attachment":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2673"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2673"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2673"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}