Max Planck's strong form of the third law of thermodynamics states the entropy of a perfect crystal vanishes at absolute zero. In such a circumstance, pure substances can (ideally) form perfect crystals with no structural imperfections as T → 0. Thermodynamics near absolute zero Īt temperatures near 0 K (−273.15 ☌ −459.67 ☏), nearly all molecular motion ceases and Δ S = 0 for any adiabatic process, where S is the entropy. Scientists and technologists routinely achieve temperatures close to absolute zero, where matter exhibits quantum effects such as Bose–Einstein condensate, superconductivity and superfluidity. Even a system at absolute zero, if it could somehow be achieved, would still possess quantum mechanical zero-point energy, the energy of its ground state at absolute zero the kinetic energy of the ground state cannot be removed. The laws of thermodynamics indicate that absolute zero cannot be reached using only thermodynamic means, because the temperature of the substance being cooled approaches the temperature of the cooling agent asymptotically. In the quantum-mechanical description, matter at absolute zero is in its ground state, the point of lowest internal energy. It is commonly thought of as the lowest temperature possible, but it is not the lowest enthalpy state possible, because all real substances begin to depart from the ideal gas when cooled as they approach the change of state to liquid, and then to solid and the sum of the enthalpy of vaporization (gas to liquid) and enthalpy of fusion (liquid to solid) exceeds the ideal gas's change in enthalpy to absolute zero. The corresponding Kelvin and Rankine temperature scales set their zero points at absolute zero by definition. The theoretical temperature is determined by extrapolating the ideal gas law by international agreement, absolute zero is taken as −273.15 degrees on the Celsius scale ( International System of Units), which equals −459.67 degrees on the Fahrenheit scale ( United States customary units or imperial units). The fundamental particles of nature have minimum vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion. Zero kelvin (−273.15 ☌) is defined as absolute zero.Ībsolute zero is the lowest limit of the thermodynamic temperature scale a state at which the enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as zero kelvin. JSTOR ( December 2022) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.
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