absolute zero

(noun)

The coldest possible temperature: zero on the Kelvin scale and approximately -273.15°C and -459.67°F. The total absence of heat; the temperature at which motion of all molecules would cease.

Related Terms

Examples of absolute zero in the following topics:

  • Absolute Zero

    • Absolute zero is the coldest possible temperature; formally, it is the temperature at which entropy reaches its minimum value.
    • Absolute zero is universal in the sense that all matteris in ground state at this temperature .
    • To be precise, a system at absolute zero still possesses quantum mechanical zero-point energy, the energy of its ground state.
    • The zero point of a thermodynamic temperature scale, such as the Kelvin scale, is set at absolute zero.
    • Explain why absolute zero is a natural choice as the null point for a temperature unit system

  • The Third Law

    • According to the third law of thermodynamics, the entropy of a perfect crystal at absolute zero is exactly equal to zero.
    • The third law of thermodynamics is sometimes stated as follows: The entropy of a perfect crystal at absolute zero is exactly equal to zero.
    • Nernst proposed that the entropy of a system at absolute zero would be a well-defined constant.
    • Instead of being 0, entropy at absolute zero could be a nonzero constant, due to the fact that a system may have degeneracy (having several ground states at the same energy).
    • In simple terms, the third law states that the entropy of a perfect crystal approaches zero as the absolute temperature approaches zero.

  • Kelvin Scale

    • The kelvin is a unit of measurement for temperature; the null point of the Kelvin scale is absolute zero, the lowest possible temperature.
    • The Kelvin scale is an absolute, thermodynamic temperature scale using absolute zero as its null point.
    • In the classical description of thermodynamics, absolute zero is the temperature at which all thermal motion ceases.
    • The choice of absolute zero as null point for the Kelvin scale is logical.
    • Subtracting 273.16K from the temperature of the triple point of water, 0.01°C, makes absolute zero (0K) equivalent to -273.15°C and -460°F .

  • Adiabatic Processes

    • It is impossible to reduce the temperature of any system to zero temperature in a finite number of finite operations.
    • In this Atom, we discuss an adiabatic cooling process that can be used to cool a gas, as well as whether absolute zero can be obtained in real systems.
    • Previously, we learned about the third law of thermodynamics, which states: the entropy of a perfect crystal at absolute zero is exactly equal to zero.
    • Assuming an entropy difference at absolute zero, T=0 could be reached in a finite number of steps.
    • Left side: Absolute zero can be reached in a finite number of steps if S(T=0,X1)≠S(T=0, X2).

  • Absolute Temperature

    • Thermodynamic temperature is an "absolute" scale because it is the measure of the fundamental property underlying temperature: its null or zero point ("absolute zero") is the temperature at which the particle constituents of matter have minimal motion and cannot become any colder.
    • Therefore, it is reasonable to choose absolute zero, where all classical motion ceases, as the reference point (T=0) of our temperature system .
    • By international agreement, the unit kelvin and its scale are defined by two points: absolute zero and the triple point of Vienna Standard Mean Ocean Water (water with a specified blend of hydrogen and oxygen isotopes).
    • Absolute zero, the lowest possible temperature, is defined precisely as 0 K and −273.15 °C.
    • Note that all of the graphs extrapolate to zero pressure at the same temperature

  • Global Warming Revisited

    • This brings up two important points: optimized heat sinks are at absolute zero, and the longer engines dump heat into an isolated system the less efficient engines will become.
    • Unfortunately for engine efficiency, day-to-day life never operates in absolute zero.

  • Celsius Scale

    • Although these defining correlations are commonly taught in schools today, by international agreement the unit "degree Celsius" and the Celsius scale are currently defined by two different temperatures: absolute zero and the triple point of Vienna Standard Mean Ocean Water (VSMOW; specially purified water).
    • Absolute zero, the lowest temperature possible (the temperature at which matter reaches minimum entropy), is defined as being precisely 0K and -273.15°C.

  • Farenheit Scale

    • Historically, the zero point of the Fahrenheit scale was determined by evaluating a thermometer placed in brine.
    • Absolute zero (-273.15 °C, or 0K) is defined as -459.67 °F.

  • Matrix and Vector Norms

    • For scalars, the obvious answer is the absolute value.
    • The absolute value of a scalar has the property that it is never negative and it is zero if and only if the scalar itself is zero.

  • Examples

    • Note well that the convergence is slowest at the origin, where the absolute value function is not differentiable.
    • Here you can see that only the sine terms appear, and no constant (zero-frequency) term.