<story><title>&apos;Zeno effect&apos; verified: Atoms won&apos;t move while you watch</title><url>http://www.news.cornell.edu/stories/2015/10/zeno-effect-verified-atoms-wont-move-while-you-watch</url></story><parent_chain></parent_chain><comment><author>fauigerzigerk</author><text>Sometimes I feel that people writing about physics are having great fun with deliberately confusing people by making stuff sound magical and illogical.&lt;p&gt;This particular effect has nothing to do with whether or not anyone is looking at an object. It&amp;#x27;s the methods of making it visible that cause the effect.</text></comment>
<story><title>&apos;Zeno effect&apos; verified: Atoms won&apos;t move while you watch</title><url>http://www.news.cornell.edu/stories/2015/10/zeno-effect-verified-atoms-wont-move-while-you-watch</url></story><parent_chain></parent_chain><comment><author>Strilanc</author><text>If I understand correctly, what&amp;#x27;s going on is... Suppose you have a system rotating between state |0&amp;gt; and state |1&amp;gt;, like f(t) = cos(t) |0&amp;gt; + sin(t) |1&amp;gt;. If you measure at time t, you get |0&amp;gt; with probability cos(t)^2. After measuring, the system starts rotating again, but reset to |0&amp;gt; (assuming you measured that). If you measure n times per rotation period, the chance of measuring the state |0&amp;gt; every time (i.e. of effectively keeping the system in the |0&amp;gt; state) is (cos(τ&amp;#x2F;n)^2)^n per period. That converges to 100% as n gets large.&lt;p&gt;So, by measuring more and more frequently, you can effectively stop a system like that from transitioning between states.&lt;p&gt;It&amp;#x27;s an interesting example of measurement unavoidably affecting quantum systems, where the problem clearly isn&amp;#x27;t due to kicking or perturbing the state.</text></comment>