Page 18 - ScienceFocus_issue11_flipbook
P. 18
Crystals, microscopically arranged in a highly ordered fashion of molecules, are common solid
structures of many compounds and elements. The crystal? structure is distinguished by its unit cell, which
consists of at least one atom within an imaginary cube, repeated and stacked in three-dimensional space
in any direction. Snowflakes, for instance, are typically a single crystal or a conglomerate of several crystals.
Solid sodium chloride, or more commonly known as table salt, is another example of a common crystal. Or
perhaps most iconic is the giant covalent network of diamond. These tangible structures are easy to grasp,
because they exist in space. Yet, in 2012, the same idea of a repeated structural unit in time was proposed
by Nobel laureate Frank Wilczek, known as a time crystal.
These abstract structures would pulse without the need of energy input. Instead of a repeating unit of
molecules that extend in all directions of a crystal lattice in space, a time crystal would theoretically consist
?啁鞈芰???
???園?
A New State of Matter:
By Long Him Cheung 撘菜?雓?
?園??臬虜閬??粹?蝯?嚗凝閫????擃漲?????撠???摮??桀??嗉?嚗??寧?摮?其?蝬剔征??
銝剝?銴???敶Ｘ??園?蝯???摮??芾嚗??臬?園????擃????押??粹?瘞臬????單靽迂??暽踝?銋銝蝔桀虜閬?
?園???潭??瑟?隤抒?靘?嚗?質?蝞?喟?撌典??勗蝬脩?蝯????耦蝯?摮?潛征??銝哨?敺??圾?2012撟湛?隢?鞎??銝餃???嚗??曉??停隞仿?銴?瑽?璁艙嚗??箔????擃?閮剜??
?車?質情??瑽?頛詨?賡?撠梯憭??暸望??抒??????擃?蝯??桀?敺銝??孵?????嚗?隢葉??
?擃??臬??頠訾?????璅∪?嚗停???其??潭?銋瘞賊?銵粥???1] ???擃??望??扳??銝?璅????
?園????批??改?銝?祆郭?停?閬?憭?撽???撠??曉???瘛勗尼瑽?隢詨祕頦?撠梯??Ｗ?憭?Ｘ??啜?/code>
