Clausius inequality correct for negative temperature

In summary, Clausius inequality is correct for positive temperature but not for negative temperature. Negative absolute temperature is not well-defined and there is a need to adapt the statements of the second law for systems with negative temperature. This has been observed in spin systems, lasers, and translational degrees of freedom. An old article from Scientific American discusses this issue.
  • #1
persia7
39
0
is clausius inequality correct for negative temperature?, if you see the proof of it in positive temperature its not correct.
 
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  • #2
persia7 said:
is clausius inequality correct for negative temperature?, if you see the proof of it in positive temperature its not correct.

Clausius statement is just a statement of second law of thermodynamics.

Its correct.

For reversible process,

ΔStotal=0

For irreversible process:

ΔSTotal>qirrev/T

And scientists are not able to achieve exactly zero absolute temperatures. Negative absolute temperature is not even defined !
 
  • #3
sankalpmittal, negative temperatures have long been introduced, especially in spin systems and lasers, and some month ago even for translational degrees of freedom.
There is indeed some need to adapt the various statements of the second law when systems with negative temperature are present.
See, e.g. this old article from scientific american:
http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=6796844
 

Related to Clausius inequality correct for negative temperature

What is the Clausius inequality and how does it apply to negative temperatures?

The Clausius inequality is a thermodynamic principle that states that the total change in entropy in a closed system during a process will always be equal to or greater than zero. This means that the entropy of a closed system can never decrease. This applies to negative temperatures as well, as they are simply a representation of the direction of energy flow and do not violate the second law of thermodynamics.

How is negative temperature defined and what are its properties?

Negative temperature is defined as a temperature scale where the higher the numerical value, the lower the actual temperature. This means that objects at negative temperatures are hotter than objects at positive temperatures. Negative temperature also has the property that objects with negative temperatures will always transfer heat to objects with positive temperatures, never the other way around.

Why is the Clausius inequality still valid for negative temperatures?

The Clausius inequality is a fundamental principle of thermodynamics and applies to all closed systems, regardless of the temperature scale being used. It is based on the second law of thermodynamics, which states that the total entropy of a closed system will always increase or remain constant. As negative temperatures do not violate this law, the Clausius inequality remains valid for negative temperatures.

Are there any real-life applications of negative temperatures?

Yes, there are several real-life applications of negative temperatures, particularly in the field of physics. Negative temperature states can be created in laboratory settings to study the properties of certain materials and to better understand thermodynamic processes. Negative temperatures also play a role in certain physical phenomena, such as Bose-Einstein condensates and lasers.

Is it possible for objects to achieve absolute zero with negative temperatures?

No, objects cannot achieve absolute zero with negative temperatures. Absolute zero is defined as the lowest temperature possible, where all molecular motion stops. Negative temperatures are simply a representation of the direction of energy flow and do not reflect the actual temperature of an object. Absolute zero can only be reached with positive temperatures.

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