{"id":2265,"date":"2020-01-07T22:40:26","date_gmt":"2020-01-07T22:40:26","guid":{"rendered":"http:\/\/lptms.u-psud.fr\/christophe_texier\/?page_id=2265"},"modified":"2022-06-02T22:07:48","modified_gmt":"2022-06-02T22:07:48","slug":"fluctuations-and-single-parameter-scaling","status":"publish","type":"page","link":"http:\/\/www.lptms.universite-paris-saclay.fr\/christophe_texier\/recherche\/some-properties-of-the-one-dimensional-schrodinger-operator-with-random-potential\/fluctuations-and-single-parameter-scaling\/","title":{"rendered":"Fluctuations and single parameter scaling"},"content":{"rendered":"<h3>Localization properties with potential with large local fluctuations<\/h3>\n<p>Most of works on 1D Anderson localisation consider the case where the potential has relatively small local fluctuations, such that &lt;<em>V<\/em><sub>n<\/sub> <sup>2<\/sup>&gt; &lt; \u221e (<em>V<\/em><sub>n<\/sub> is the on-site potenial for discrete models) or \u222b<sub>-\u221e<\/sub><sup>+\u221e<\/sup>d<em>x<\/em> &lt;<em>V<\/em>(<em>x<\/em>)<em>V<\/em>(0)&gt; &lt; \u221e (for continuous models). Models where this condition is not fulfilled lead to non standard localization properties (super-localisation) with non exponential damping of wave function&rsquo;s envelope, like exp(-|<em>x<\/em>|<sup>\u03b1<\/sup>) for \u03b1&gt;1.<\/p>\n<ul>\n<li>Tom Bienaim\u00e9 and Christophe Texier,<br \/>\n<strong>Localization for one-dimensional random potentials with large local fluctuations<\/strong><br \/>\n<a href=\"http:\/\/iopscience.iop.org\/1751-8121\/41\/47\/475001\">J. Phys. A: Math. Theor. <strong>41<\/strong>, 475001 (2008).<\/a> (9pp)<br \/>\n<a href=\"http:\/\/arxiv.org\/abs\/0807.0772\">cond-mat arXiv:0807.0772.<\/a><\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h3>Fluctuations of random matrix products of SL(2,R) and localisation in the random mass Dirac equation<\/h3>\n<p>We study the <em>fluctuations<\/em> of the logarithm of the wave functions, a problem related to the analysis of the fluctuations of certain random matrix products:<\/p>\n<ul>\n<li>Kabir Ramola and Christophe Texier,<br \/>\n<strong>Fluctuations of random matrix products and 1D Dirac equation with random mass<\/strong>,<br \/>\n<a href=\"http:\/\/link.springer.com\/article\/10.1007%2Fs10955-014-1082-z\"> J. Stat. Phys. <strong>157<\/strong>, 497-514 (2014)<\/a><br \/>\n<a href=\"http:\/\/arxiv.org\/abs\/1402.6943\">cond-mat arXiv:1402.6943<\/a><\/li>\n<\/ul>\n<p>This question is of importance in localisation problems : it is related to the discussion of the Single Parameter Scaling hypothesis ; this plays an important role when studying statistical properties of local density of states (Altshuler &amp; Prigodin, 1989) or Wigner time delay (Texier &amp; Comtet, <a href=\"http:\/\/prl.aps.org\/abstract\/PRL\/v82\/i21\/p4220_1\">Phys. Rev. Lett. <strong>82<\/strong>(21), 4220 (1999)<\/a>).<\/p>\n<p style=\"padding-left: 60px\"><strong><span style=\"color: #ff0000\">See also<\/span> page \u201c <a href=\"http:\/\/lptms.u-psud.fr\/christophe_texier\/recherche\/random-matrix-theory\/products-of-random-matrices\/\">products of random matrices<\/a> \u201d<\/strong><\/p>\n<h3>Fluctuations and single parameter scaling for 1D disorder<\/h3>\n<p>The \u00ab\u00a0single parameter scaling\u00a0\u00bb (SPS) hypothesis is a corner stone of the scaling theory of localization. It states that the full distribution of observable is controlled by a single characteristic scale (the localization length). First discussed within models with ad hoc random phase assumption (see the nice article: Cohen, Roth &amp; Shapiro, <a href=\"https:\/\/journals.aps.org\/prb\/abstract\/10.1103\/PhysRevB.38.12125\">Phys. Rev. B <strong>38<\/strong>, 12125 (1988)<\/a>), the solvable Lloyd model has provided a ground to test SPS within a microscopic model (Deych, Lisyansky &amp; Altshuler, <a href=\"https:\/\/journals.aps.org\/prl\/abstract\/10.1103\/PhysRevLett.84.2678\">Phys. Rev. Lett. <strong>84<\/strong>, 2678 (2000)<\/a>).<br \/>\nIn the following paper, a general formula for the variance of ln|\u03c8(x)| is obtained, where \u03c8(x) solves the Schr\u00f6dinger equation, for arbitrary disorder characterised by its L\u00e9vy exponent <em>L<\/em>(<em>s<\/em>):<\/p>\n<ul>\n<li>Christophe Texier,<br \/>\n<strong>Fluctuations of the product of random matrices and generalized Lyapunov exponent<\/strong>,<br \/>\n<a href=\"https:\/\/link.springer.com\/article\/10.1007%2Fs10955-020-02617-w\">J. Stat. Phys (2020)<\/a><br \/>\n<a href=\"http:\/\/arxiv.org\/abs\/1907.08512\">cond-mat arXiv:1907.08512<\/a><br \/>\nSome integral formula is derived for\u00a0\u03b3<sub>2<\/sub>=lim<sub><em>x<\/em>\u2192\u221e<\/sub>(1\/x)Var(ln|\u03c8(x)|) for the Schr\u00f6dinger equation with a random potential.<\/li>\n<\/ul>\n<p style=\"padding-left: 60px\"><strong><span style=\"color: #ff0000\">See also<\/span> page \u201c <a href=\"http:\/\/lptms.u-psud.fr\/christophe_texier\/recherche\/random-matrix-theory\/products-of-random-matrices\/\">products of random matrices<\/a> \u201d<\/strong><\/p>\n<p>Using this general formalism, I have provided in the previous paper a general framework allowing to analyse SPS in a very broad class of models with both finite of infinite second moment (like for the Lloyd model). A universal formula for the generalised Lyapunov exponent (cumulant generating function of ln|\u03c8(x)|) is derived:<\/p>\n<ul>\n<li>Christophe Texier,<br \/>\n<strong>Generalized Lyapunov exponent of random matrices and universality classes for SPS in 1D Anderson localisation<\/strong>,<br \/>\n<a href=\"https:\/\/iopscience.iop.org\/article\/10.1209\/0295-5075\/131\/17002\">Europhys. Lett. 131, 17002 (2020)<\/a><br \/>\n<a href=\"http:\/\/arxiv.org\/abs\/1910.01989\">cond-mat arXiv:1910.01989<\/a><br \/>\nUsing the general formalism of the previous article, the Single Parameter Scaling for Anderson localization is proven within a general framework, and extended to potentials with large fluctuations (such that &lt;V<sup>2<\/sup>&gt;=\u221e)<\/li>\n<li>Alain Comtet, Christophe Texier &amp; Yves Tourigny,<br \/>\n<strong>The generalized Lyapunov exponent for the one-dimensional Schr\u00f6dinger equation with Cauchy disorder: some exact results<\/strong>,<br \/>\n<a href=\"http:\/\/arxiv.org\/abs\/2110.01522\">cond-mat arXiv:2110.01522<\/a><br \/>\nTaking advantage of the specificity of the Lloyd model, we are able to get a secular equation for the generalized Lyapunov exponent, from which we derive a set of exact results<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Localization properties with potential with large local fluctuations Most of works on 1D Anderson localisation consider the case where the potential has relatively small local fluctuations, such that &lt;Vn 2&gt; &lt; \u221e (Vn is the on-site potenial for discrete models) &hellip; <a href=\"http:\/\/www.lptms.universite-paris-saclay.fr\/christophe_texier\/recherche\/some-properties-of-the-one-dimensional-schrodinger-operator-with-random-potential\/fluctuations-and-single-parameter-scaling\/\">Continuer la lecture <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":7,"featured_media":0,"parent":42,"menu_order":15,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2265","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/www.lptms.universite-paris-saclay.fr\/christophe_texier\/wp-json\/wp\/v2\/pages\/2265","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.lptms.universite-paris-saclay.fr\/christophe_texier\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/www.lptms.universite-paris-saclay.fr\/christophe_texier\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/www.lptms.universite-paris-saclay.fr\/christophe_texier\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"http:\/\/www.lptms.universite-paris-saclay.fr\/christophe_texier\/wp-json\/wp\/v2\/comments?post=2265"}],"version-history":[{"count":6,"href":"http:\/\/www.lptms.universite-paris-saclay.fr\/christophe_texier\/wp-json\/wp\/v2\/pages\/2265\/revisions"}],"predecessor-version":[{"id":2648,"href":"http:\/\/www.lptms.universite-paris-saclay.fr\/christophe_texier\/wp-json\/wp\/v2\/pages\/2265\/revisions\/2648"}],"up":[{"embeddable":true,"href":"http:\/\/www.lptms.universite-paris-saclay.fr\/christophe_texier\/wp-json\/wp\/v2\/pages\/42"}],"wp:attachment":[{"href":"http:\/\/www.lptms.universite-paris-saclay.fr\/christophe_texier\/wp-json\/wp\/v2\/media?parent=2265"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}