By Frédéric Chevy, Ecole Normale Supérieure
Image: Artist's view of atoms in an optical lattice. When the atomic density is extremely high, the atoms block each other’s way, and atoms are stuck at the bottom of their optical wells.
For a hundred years now, we have known that some compounds lose their electrical resistance at low temperatures, a phenomenon known as superconductivity. Electrical current flows without resistance in these materials, offering unique possibilities such as carrying electrical current without loss or storing electrical energy for a nearly infinite time. However, even for the “hottest” compounds (known as high critical temperature superconductors), superconductivity only happens below about 150 degrees Celsius, a temperature way too low for large-scale practical applications.