<story><title>Physicists Create World’s First Time Crystal</title><url>https://www.technologyreview.com/s/602541/physicists-create-worlds-first-time-crystal/</url></story><parent_chain><item><author>lisper</author><text>You&amp;#x27;re not that far off.  The particles aren&amp;#x27;t really &lt;i&gt;moving&lt;/i&gt;, i.e. they are not going from one spatial location to another.  What is happening is that they are changing quantum spin states, and the spin states are changing in such a way that it appears that a circular arrangement of atoms is rotating.  This is a reflection of the fact that an atom isn&amp;#x27;t really a &lt;i&gt;thing&lt;/i&gt; (there are no &amp;quot;things&amp;quot;, i.e. there are no particles) it&amp;#x27;s just a quantum state, so if you have a quantum system A in state 1 and system B in state 2, and system A transitions to state 2 and system B transitions to state 1 then this end result is indistinguishable from the two systems having swapped locations.  We call this &amp;quot;moving&amp;quot; because classical motion is the only mechanism we&amp;#x27;re familiar with in everyday life that allows two systems to swap locations.  But that kind of moving is not what is happening here.</text></item><item><author>davesque</author><text>I figured this article would fly over my head (which it mostly did), but it was actually a very fun read.  My main takeaway was the paradox that the interesting arrangement of matter could be in its lowest energy state, yet still moving.  And that no energy could be extracted from this movement.  I&amp;#x27;m probably butchering the concept with my misuse of terminology but whatevs.</text></item></parent_chain><comment><author>ams6110</author><text>Sounds almost like how words appear to be moving across a scrolling led (or previously, incandescent bulb) display, when nothing is moving it&amp;#x27;s just each led&amp;#x2F;bulb switching from lit to unlit.</text></comment>
<story><title>Physicists Create World’s First Time Crystal</title><url>https://www.technologyreview.com/s/602541/physicists-create-worlds-first-time-crystal/</url></story><parent_chain><item><author>lisper</author><text>You&amp;#x27;re not that far off.  The particles aren&amp;#x27;t really &lt;i&gt;moving&lt;/i&gt;, i.e. they are not going from one spatial location to another.  What is happening is that they are changing quantum spin states, and the spin states are changing in such a way that it appears that a circular arrangement of atoms is rotating.  This is a reflection of the fact that an atom isn&amp;#x27;t really a &lt;i&gt;thing&lt;/i&gt; (there are no &amp;quot;things&amp;quot;, i.e. there are no particles) it&amp;#x27;s just a quantum state, so if you have a quantum system A in state 1 and system B in state 2, and system A transitions to state 2 and system B transitions to state 1 then this end result is indistinguishable from the two systems having swapped locations.  We call this &amp;quot;moving&amp;quot; because classical motion is the only mechanism we&amp;#x27;re familiar with in everyday life that allows two systems to swap locations.  But that kind of moving is not what is happening here.</text></item><item><author>davesque</author><text>I figured this article would fly over my head (which it mostly did), but it was actually a very fun read.  My main takeaway was the paradox that the interesting arrangement of matter could be in its lowest energy state, yet still moving.  And that no energy could be extracted from this movement.  I&amp;#x27;m probably butchering the concept with my misuse of terminology but whatevs.</text></item></parent_chain><comment><author>davesque</author><text>Thanks for the great explanation.  Serious question: Can I ask how you happen to know so much about this subject?</text></comment>