Room-Temperature Quantum Bit Memory Exceeding One Second

<jats:title>Extending Quantum Memory</jats:title> <jats:p> Practical applications in quantum communication and quantum computation require the building blocks—quantum bits and quantum memory—to be sufficiently robust and long-lived to allow for manipulation and storage (see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6086" page="1239" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1223439">Boehme and McCarney</jats:related-article> </jats:bold> ). <jats:bold> Steger <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="1280" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1217635">1280</jats:related-article> ) demonstrate that the nuclear spins of <jats:sup>31</jats:sup> P impurities in an almost isotopically pure sample of <jats:sup>28</jats:sup> Si can have a coherence time of as long as 192 seconds at a temperature of ∼1.7 K. In diamond at room temperature, <jats:bold> Maurer <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="1283" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1220513">1283</jats:related-article> ) show that a spin-based qubit system comprised of an isotopic impurity ( <jats:sup>13</jats:sup> C) in the vicinity of a color defect (a nitrogen-vacancy center) could be manipulated to have a coherence time exceeding one second. Such lifetimes promise to make spin-based architectures feasible building blocks for quantum information science. </jats:p>