Macroscopic quantum phenomena in the context of Laser

Ice is water that is frozen into a solid state, typically forming at or below temperatures of 0 °C, 32 °F, or 273.15 K. It occurs naturally on Earth, on other planets, in Oort cloud objects, and as interstellar ice. As a naturally occurring crystalline inorganic solid with an ordered structure, ice is considered to be a mineral. Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaque bluish-white color.

Virtually all of the ice on Earth is of a hexagonal crystalline structure denoted as ice I_h (spoken as "ice one h"). Depending on temperature and pressure, at least nineteen phases (packing geometries) can exist. The most common phase transition to ice I_h occurs when liquid water is cooled below 0 °C (273.15 K, 32 °F) at standard atmospheric pressure. When water is cooled rapidly (quenching), up to three types of amorphous ice can form. Interstellar ice is overwhelmingly low-density amorphous ice (LDA), which likely makes LDA ice the most abundant type in the universe. When cooled slowly, correlated proton tunneling occurs below −253.15 °C (20 K, −423.67 °F) giving rise to macroscopic quantum phenomena.

In condensed matter physics, a Bose–Einstein condensate (BEC) is a state of matter that is typically formed when a gas of bosons at very low densities is cooled to temperatures very close to absolute zero, i.e. 0 K (−273.15 °C; −459.67 °F). Under such conditions, a large fraction of bosons occupy the lowest quantum state, at which microscopic quantum-mechanical phenomena, particularly wavefunction interference, become apparent macroscopically.More generally, condensation refers to the appearance of macroscopic occupation of one or several states: for example, in BCS theory, a superconductor is a condensate of Cooper pairs. As such, condensation can be associated with phase transition, and the macroscopic occupation of the state is the order parameter.

Bose–Einstein condensates were first predicted, generally, in 1924–1925 by Albert Einstein, crediting a pioneering paper by Satyendra Nath Bose on the new field now known as quantum statistics. In 1995, the Bose–Einstein condensate was created by Eric Cornell and Carl Wieman of the University of Colorado Boulder using rubidium atoms. Later that year, Wolfgang Ketterle of MIT produced a BEC using sodium atoms. In 2001 Cornell, Wieman, and Ketterle shared the Nobel Prize in Physics "for the achievement of Bose–Einstein condensation in dilute gases of alkali atoms, and for early fundamental studies of the properties of the condensates".

John Clarke (born 10 February 1942) is a British experimental physicist and Professor Emeritus at the University of California, Berkeley. He is known for his various works on measurement devices based on superconductivity. Steven Girvin has called Clarke "the godfather of superconducting electronics".

In the 1980s, Clarke led a research team, that included John M. Martinis and Michel Devoret. Their discoveries in macroscopic quantum phenomena using the Josephson effect earned them the Nobel Prize in Physics in 2025.

John Matthew Martinis (born 1958) is an American physicist and Professor of Physics at the University of California, Santa Barbara. He led a team to develop a superconducting quantum computer at Google Quantum AI Lab, a partnership between UC Santa Barbara and Google. With the Sycamore processor, they claimed the first evidence of quantum supremacy in 2019.

He shared the 2025 Nobel Prize in Physics with John Clarke and Michel Devoret for their joint work on macroscopic quantum phenomena in superconductors.

Michel Henri Devoret (French pronunciation: [miʃɛl dəvɔʁɛ]; born 5 March 1953) is a French-American physicist. He is Professor of Physics at the University of California, Santa Barbara, and Professor Emeritus of Applied Physics at Yale University. He serves as the Chief Scientist for Quantum Hardware at Google Quantum AI. He is known for the development of various superconducting quantum computing architectures, including the quantronium, the transmon, and the fluxonium.

He shared the 2025 Nobel Prize in Physics with John Clarke and John M. Martinis for their joint work on macroscopic quantum phenomena in superconducting circuits.