A new spin on condensed-matter physics using two-level atoms. (General Development).The incredibly long coherence times of atomic hyperfine states make them ideally suited for frequency standards and quantum information In quantum mechanics, quantum information is physical information that is held in the "state" of a quantum system. The most popular unit of quantum information is the qubit, a two-state quantum system. processing. Recent experiments on quantum gases have utilized this cherished trait of cold atoms for the study of spin waves, a property usually associated with solid-state materials rather than dilute atomic gases. NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. researchers have imaged the spatial structure of a standing spin wave for the first time in a dilute gas. The effect was seen in a gas of rubidium-87 atoms, cooled just above the transition temperature for BoseEinstein condensation. NIST theorists teamed up with the experimentalists for a detailed study of the excitation excitation Addition of a discrete amount of energy to a system that changes it usually from a state of lowest energy (ground state) to one of higher energy (excited state). For example, in a hydrogen atom, an excitation energy of 10. frequencies and damping damping In physics, the restraint of vibratory motion, such as mechanical oscillations, noise, and alternating electric currents, by dissipating energy. Unless a child keeps pumping a swing, the back-and-forth motion decreases; damping by the air's friction opposes the rates of the collective spin modes. Their joint work was published in the Aug. 26 issue of Physical Review Letters Physical Review Letters is one of the most prestigious journals in physics.[1] Since 1958, it has been published by the American Physical Society as an outgrowth of The Physical Review. [Phys. Rev. Left. 89, 090402 (2002)]. Details of the theory appeared in a separate article in Physical Review A [Phys. Rev. A 66, 043411 (2002)]. This work emphasizes the crucial role that the internal coherence can play in collective properties of cold gases and has immediate relevance to the very active area of research on two-component Fermi gases. CONTACT: Jamie Williams, (301) 975-5297; jamiew@nist.gov. |
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