3) The number of quantum states accessible to a certain system is [tex]$\Omega$[/tex] and entropy is [tex]$S = k \ln \Omega$[/tex].

First, by writing the entropy in terms of [tex]$V$[/tex] and [tex]$E$[/tex], find the temperature, pressure, and chemical potential for the following values of accessible states [tex]$\Omega$[/tex]:

(a) [tex]$\Omega = e^{2 V^{4 / 5}} E^{2 V}$[/tex] [tex]\[ (G1, G3) \][/tex]

(b) [tex]$\Omega = 2 e^{-V^{1 / 2}} E^{3 V}$[/tex] [tex]\[ (G2, G4) \][/tex]

(c) [tex]$\Omega = e^{2 N V^2} E^{N V}$[/tex] [tex]\[ (G5, G6) \][/tex]



Answer :

Certainly! Let's address the problem of finding temperature, pressure, and chemical potential for the given values of accessible states [tex]\(\Omega\)[/tex]. The entropy [tex]\(S\)[/tex] for a system is given by [tex]\(S = k_B \ln \Omega\)[/tex], where [tex]\(k_B\)[/tex] is Boltzmann's constant. We'll use this relationship and the thermodynamic definitions to find the quantities.

### (a) [tex]\(\Omega = e^{2 V^{4/5}} E^{2 V}\)[/tex]

1. Entropy ([tex]\(S\)[/tex]):
[tex]\[ S = k_B \ln \Omega = k_B \ln \left(e^{2 V^{4/5}} E^{2 V}\right) = k_B \left( 2 V^{4/5} + 2 V \ln E\right) \][/tex]

2. Temperature ([tex]\(T\)[/tex]):
Using [tex]\( \frac{1}{T} = \left( \frac{\partial S}{\partial E} \right)_{V,N} \)[/tex]:
[tex]\[ \frac{\partial S}{\partial E} = k_B \left( 2V \cdot \frac{1}{E} \right) = \frac{2k_B V}{E} \][/tex]
Hence,
[tex]\[ \frac{1}{T} = \frac{2 k_B V}{E} \implies T = \frac{E}{2 k_B V} \][/tex]

3. Pressure ([tex]\(P\)[/tex]):
Using [tex]\( \frac{P}{T} = \left( \frac{\partial S}{\partial V} \right)_{E,N} \)[/tex]:
[tex]\[ \frac{\partial S}{\partial V} = k_B \left( \frac{8}{5}V^{-1/5} + 2 \ln E \right) \][/tex]
So,
[tex]\[ \frac{P}{T} = \frac{1}{T} k_B \left( \frac{8}{5}V^{-1/5} + 2 \ln E \right) \][/tex]
Using [tex]\( T = \frac{E}{2 k_B V} \)[/tex],
[tex]\[ P = T \cdot k_B \left( \frac{8}{5}V^{-1/5} + 2 \ln E \right) = \frac{E}{2V} \left( \frac{8}{5} V^{-1/5} + 2 \ln E \right) \][/tex]

4. Chemical Potential ([tex]\(\mu\)[/tex]):
For a system not explicitly dependent on the number of particles [tex]\(N\)[/tex], the chemical potential [tex]\(\mu\)[/tex] may not be clearly derivable from the given expression without additional dependency terms. Assuming [tex]\(\Omega\)[/tex] is independent of [tex]\(N\)[/tex], [tex]\(\mu\)[/tex] would require more context or assumptions about [tex]\(N\)[/tex] to define.

### (b) [tex]\(\Omega = 2 e^{-V^{1/2}} E^{3 V}\)[/tex]

1. Entropy ([tex]\(S\)[/tex]):
[tex]\[ S = k_B \ln \Omega = k_B \ln \left( 2 e^{-V^{1/2}} E^{3 V} \right) = k_B \left( \ln 2 - V^{1/2} + 3 V \ln E \right) \][/tex]

2. Temperature ([tex]\(T\)[/tex]):
[tex]\[ \frac{\partial S}{\partial E} = k_B \left( 3 V \cdot \frac{1}{E} \right) = \frac{3 k_B V}{E} \][/tex]
Hence,
[tex]\[ \frac{1}{T} = \frac{3 k_B V}{E} \implies T = \frac{E}{3 k_B V} \][/tex]

3. Pressure ([tex]\(P\)[/tex]):
[tex]\[ \frac{\partial S}{\partial V} = k_B \left( - \frac{1}{2} V^{-1/2} + 3 \ln E \right) \][/tex]
So,
[tex]\[ \frac{P}{T} = \frac{1}{T} k_B \left( - \frac{1}{2} V^{-1/2} + 3 \ln E \right) \][/tex]
Using [tex]\( T = \frac{E}{3 k_B V} \)[/tex],
[tex]\[ P = T \cdot k_B \left( - \frac{1}{2} V^{-1/2} + 3 \ln E \right) = \frac{E}{3V} \left( - \frac{1}{2} V^{-1/2} + 3 \ln E \right) \][/tex]

4. Chemical Potential ([tex]\(\mu\)[/tex]):
Similar to part (a), the dependency on [tex]\(N\)[/tex] is not evident, and hence more context or explicit functional form in terms of [tex]\(N\)[/tex] is needed to clearly define [tex]\(\mu\)[/tex].

### (c) [tex]\(\Omega = e^{2 N V^2} E^{N V}\)[/tex]

1. Entropy ([tex]\(S\)[/tex]):
[tex]\[ S = k_B \ln \Omega = k_B \ln \left(e^{2 N V^2} E^{N V}\right) = k_B \left( 2 N V^2 + N V \ln E \right) \][/tex]

2. Temperature ([tex]\(T\)[/tex]):
[tex]\[ \frac{\partial S}{\partial E} = k_B \left( N V \cdot \frac{1}{E} \right) = \frac{k_B N V}{E} \][/tex]
Hence,
[tex]\[ \frac{1}{T} = \frac{k_B N V}{E} \implies T = \frac{E}{k_B N V} \][/tex]

3. Pressure ([tex]\(P\)[/tex]):
[tex]\[ \frac{\partial S}{\partial V} = k_B \left( 4 N V + N \ln E \right) \][/tex]
So,
[tex]\[ \frac{P}{T} = \frac{1}{T} k_B \left( 4 N V + N \ln E \right) \][/tex]
Using [tex]\( T = \frac{E}{k_B N V} \)[/tex],
[tex]\[ P = T \cdot k_B \left( 4 N V + N \ln E \right) = \frac{E}{V} \left( 4 N V + N \ln E \right) \][/tex]

4. Chemical Potential ([tex]\(\mu\)[/tex]):
[tex]\[ \mu = -T \left( \frac{\partial S}{\partial N} \right)_{E,V} \][/tex]
[tex]\[ \frac{\partial S}{\partial N} = k_B \left( 2 V^2 + V \ln E \right) \][/tex]
Hence,
[tex]\[ \mu = - \left( \frac{E}{k_B N V} \right) k_B \left( 2 V^2 + V \ln E \right) = - \frac{E}{V} \left( 2 V^2 + V \ln E \right) \][/tex]

These steps provide the comprehensive solutions for temperature, pressure, and (when possible) chemical potential for each case based on the thermodynamic definition and logarithmic form of entropy.