Thermodynamic processes that occur without exchanging heat between the system and its environment.

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How can a reversible adiabatic expansion not increase entropy?

In the second stage of the Carnot cycle, a gas is thermally insulated and allowed to expand and do work on the piston. I understand the reason people give is that because entropy is $\,dS = \,dQ/T$ ...
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What is the ratio of Poisson's number for air? [on hold]

Is the ratio of Poisson's number for air between $-1$ and $\frac{1}{2}$? Thanks for replies.
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Show that change in internal energy equals zero for an adiabatic process with incompressible fluid

I have a problem when solving an exercise in thermodynamics. I am supposed to show that when we have an open system, where the process is adiabatic with an incompressible fluid, it follows that the ...
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Adiabatic Theorem in Terms of Eigenvector Derivatives

The necessary conditions for quantum Adiabatic Theorem validity is usually stated in terms of eigenvalue gaps for parameterized Hermitian matrices, or Hamiltonians. If $H(t)$ is a parameterized ...
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Modeling simple laser induced population transfer via adiabatic passage in python [migrated]

I'm trying to model adiabatic passage between two levels in a three-level atom interacting with two laser fields using Scipy and Numpy.. I'm not sure if my model is wrong due to my incorrectly ...
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Temperature change in adiabatic free expansion

Consider a gas with fixed number of particles $N$ undergoing adiabatic free expansion from $V_1$ to $V_2$. Apparently we have the following relation $$\Delta ...
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Does a closed system with fixed entropy imply an isolated system?

Just first to clarify, my university notation is $$\text{change in entropy} = \text{entropy flow} + \text{internal production of entropy}$$ I am confused with the term fixed entropy. Does that mean ...
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What are the state variables like temperature after the system has done an adiabatic irreversible process? [closed]

Consider a system containing ideal gas which is initially at a volume $V_{1}$ and then suddenly its volume is increased to a volume $V_{2}$. What is the final temperature of the system if the initial ...
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Thermodynamics of expanding nitrogen bubble as it rises in water

Problem An air bubble is released from a nitrogen tank 20 meters under water. The bubble has a radius of 1 mm. What will be the radius of the bubble when it reaches the surface? My Questions Is it ...
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What is the criterion for a change to be adiabatic?

I'm trying to understand whether the change of a parameter $\lambda$ of a Hamiltonian $H$ is adiabatic. Reading Landau and Lifshitz "Mechanics", I see ... let us suppose that $\lambda$ varies ...
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Are sound waves adiabatic or isothermal?

I am doing a presentation on sound waves and I need to know if they are adiabatic or isothermal. I know that they can generate heat, but is the amount of heat created so small that it can still be ...
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thermodynamics poisson's ratio of mixtures

air consists of 79% nitrogen and 21% diatomic gas(say) . to perform calculations on ΔH on adiabatic expansions, instead of taking as parts , can i take it as a uniform gas with some γ(poission's ...
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primordial perturbations

According to cosmic inflation, primordial perturbations are adiabatic. As in, the fractional number density of all types of particles is the same, n_baryons = n_photons etc. But what would it mean if ...
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scattering by weak potential and the adiabatic hypothesis

In Ryder QFT, regarding the calculation of the scattering amplitude by a weak potential $V$, the potential is assumed to be switched on and off slowly using the adiabatic hypothesis. But there is a ...
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Isentropic process and reversibility [duplicate]

I know that every adiabatic reversible process is an isentropic process. Can a process be isentropic but still not reversible adiabatic? Please provide me some examples.
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Does no variables change in an adiabatic + isothermal system?

Adiabatic + isothermal = no heat and temperature change. Does that mean the system will remain as it is? If it is adiabatic + isovolumetric or adiabatic + isobaric , is it as well no change in any ...
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What is the difference between reversible and irreversible adiabatic expansion?

What is the difference between reversible and irreversible adiabatic expansion? Is it true that the work done by the gas is the same but the pressure applied externally differ between two process? ...
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Comparison between isobaric, isothermal and adiabatic expansion

Please check if my understandings of these terms are right because they are a bit confusing to me. For all three types of expansions, a change in volume means work is done by the system to the ...
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Dry adiabatic lifting

If an unsaturated air parcel ascends adiabatically in the atmosphere with an initial temperature, would the final temperature of the air parcel, when it reaches it's destination, be the same at the ...
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Difference between non-adiabatic coupling and diagonal Born Oppenheimer correction?

I think my question is quite well formulated in the title! I'm trying to understand collision process involving crossing between different electronic states in the potential energy surface, which ...
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Steady-state adiabatic nozzle, unknown exit velocity & temperature [closed]

The question is 2.10 taken from: Introductory Chemical Engineering Thermodynamics, 2E by Elliot,Lira Air at 30ºC and 2MPa flows ata steady state in a horizontal pipeline with a velocity of 25m/s. ...
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Eigenvalue of the adiabatic Hamiltonian of Farhi's three qubit 2-SAT problem

I was trying to reproduce example 3.3 of Quantum Computation by Adiabatic Evolution by Edward Farhi et. al. This is an adiabatic algorithm to solve an instance of three qubits 2-SAT problem. I think ...
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Is it possible to change one quantum state to another state by a cyclic adiabatic process?

An example is applying magnetic flux through the axis of a cylinder (2D system with periodic boundary condition). When changing flux from 0 to 1 flux quanta adiabatically, it seems that we can ...
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Does the entropy of an adiabatically isolated system stays the same after we decrease/increase the pressure?

Even if the system is isolated and there is no heat exchange with surroundings, shouldn't the decrease/increase of pressure result in increase/decrease of entropy? Does this property of an ...
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Different forms of the Adiabatic Theorem

I've been reading several papers on Adiabatic Quantum Computation, and I am confused by the form in which the adiabatic approximation condition is presented. For example (quant-ph/0001106 eq 2.8) ...
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How to understand the indeterminate process in thermodynamics?

Consider a closed composite system with an internal movable adiabatic wall. If we release the piston, thermodynamics cannot determine the final equilibrium state (the temperature cannot be ...
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Can we apply $pV^\gamma$=const only for quasistatic adiabatic process?

But If this is so, I have often seen people applying this formula for quick processes where no heat exchange is possible. Here is an example from where I am quoting the following: we will assume ...
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Schrodinger basis kets with Time-dependent Hamiltonian

I was reading through the proof of the Adiabatic Theorem (in Sakurai) and I realised I'm not quite sure how Schrodinger Basis kets behave when we have a time-dependent Hamiltonian. I know that with a ...
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Adiabatic expansion in the atmosphere

When an air parcel rises and cools adiabatically, it is said that there is no heat transfer as work is done on the surrounding atmosphere as the parcel expands. The parcel loses internal energy and ...
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A question about the energy of turning on and off interaction adiabatically in QFT

I read a saying as follows: In a theory with no particles which decay and no bound states, the turning on and off of the interactions merely serves to limit the effective range of forces. In this ...
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How do spin orientations change during adiabatic demagnetization of paramagnet?

Suppose a paramagnetic solid is taken on the following cycle, where $B_1 > B_2$ (1)->(2)->(3) I'm trying to explain what happens to occupation numbers in magnetic levels. Step (1) As $B_1$ ...
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Formula for molar specific heat capacity in polytropic process

I found this formula for a polytropic process, defined by $PV^n = {\rm constant}$, in a book: $$C = \frac R{\gamma-1} + \frac R{1-n} $$ where $C$ is molar specific heat and $\gamma$ is adiabatic ...
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Why is adiabatic process isentropic?

I have read that adiabatic process is isentropic because there is no heat exchange in an adiabatic process and thus no change in entropy. But my question is - Even in adiabatic process, work can be ...
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Adiabatic approximation and time-dependent problems

I am an undergraduate physics student. I have a question in approximation methods for time-dependent problems in quantum mechanics. I read the proof of the adiabatic theorem but I didn't understand ...
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Adiabatic Expansion with expanding control volume

I have a tube with a length $L$ and diameter $d$ that is open on 1 side. At a certain point (say $x$) from the closed end of the tube, I have a gas with a high pressure. At this point, $x$, there is ...
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How do you explain the fact that when air expands freely into an evacuated chamber from a constant pressure atmosphere, its temperature increases?

I came across this paper: Baker, B. (1999). An easy to perform but often counterintuitive demonstration of gas expansion. American Journal of Physics, 67(8), 712-713. ...
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How is this process not quasi-static yet reversible?

Consider a (adiabatic) canister with a piston containing some gas kept in a vacuum. There are two weights on the canister which equalize the pressure of the gas on the piston. Assume the system is at ...
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Basic Thermodynamics: Quasistatic Adiabatic Process

I'm going through the exercises in a Thermodynamics book, just to revise and build my intuition. Right now, I'm working on: Show that for a quasistatic adiabatic process in a perfect gas, with ...
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Adiabatic approximation

The adiabatic approximation for solid state systems is rather radical. I was wondering in which cases it breaks down. As it is based on the idea of the nuclii being much heavier than the electrons I ...
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Function describing an adiabatic process

I understand that an isothermic process, plotted on a PV diagram, can be described by a rectangular hyperbola. However, now I am wondering, what about an adiabatic process, what function best ...
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Work of an adiabatic/ compresion: sign?

As far as I am concerned the adiabatic work it is given by: $$ W_{adi}=\frac{P_{f}V_{f}-P_{i}V_{i}}{\gamma -1}$$ While I have seen in other examples that it is used with $1-\gamma$ in the ...
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How does this argument imply that entropy does not change in a quasi-static adiabatic process?

I am working through some notes of Gould and Tabochnik here and I am confused by their argument showing that entropy does not change in a quasi-static adiabatic process. First, entropy is defined to ...
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Adiabatic proccess and Carnot cycle in a photon gas

I am making a comparation between the photon gas and the ideal classic gas for my Thermodynamics class. The photon gas is defined by the equations: $$U=aVT^4 $$ $$P=\dfrac{1}{3}aT^4$$ I found this ...
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How do you calculate the change in temperature of an adiabatic system?

I really don't even know how to start doing this problem. I understand PV=nRT and I understand that if either T, V, or P is kept constant, then the other 2 change at the same rate, and I understand ...
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Adiabatic expansion in van der Waals gas [closed]

Given a Van der Waals gas with state equation: $$\left( P+\frac{N^2 a}{V^2}\right)\left( V-Nb \right)=NkT,$$ show that the equation of an adiabatic process is: $$\left( ...
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139 views

Sign Paradox in Berry's Phase

Suppose we have normalized states $| n(\vec{R})\rangle$ indexed by continuous variable $\vec{R}$. Then fixing our choice of gauge and ignoring dynamic phase, the phase difference between two states ...
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Adiabatic evolution for initial Hamiltonian on Hadamard basis and problem Hamiltonian as diagonal

This is spawned from a comment at the answer to one of my previous questions. Someone suggested to me that claiming the following statement might be NP-hard. Could anyone please help me to figure out ...
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Confusion about a lemma on the time constraint of an adiabatic evolution (arXiv:quant-ph/0604077)

I am going through the paper Quantum adiabatic evolutions that can't be used to design efficient algorithms by Zhaohui Wei and Mingsheng Ying. On the second page they prove a lemma. The statement goes ...
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Are reversible adiabatic processes always isentropic?

If my understanding is correct, neither reversible nor adiabatic processes are necessarily isentropic. But are reversible adiabatic processes always isentropic?
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Why is there a sign error in my derivation? Adiabatic expansion of ideal gas: $TV^{1-\gamma}$ is constant

This is the last part of a derivation of the equation for an ideal gas undergoing reversible adiabatic expansion. I'm trying to prove that $T V^{\gamma-1}$ is constant, but my result is that $T ...