The system is immersed in an environment with a constant high temperature T. What would be the energy expectation value of the system

The energy value is expected to rise steadily until it is equal to a value that depends on the temperature T of the environment.

Explanation:

If a system is immersed into an environment with a constant high temperature, the temperature of the system will also rise until it comes to equilibrium with the temperature of the environment. When this happens, the energy expectation value of the system will now be dependent on the temperature of the environment. This means that the energy of the system will be a function of the temperature of the environment.

This means that

E = f(T)

where E is the energy value of the system

T is the temperature of the environment.