Phase Definition and 1000 Threads

  1. H

    Engineering Decomposition minimal phase & all pass

    Hey everybody! I have put G1 = (1-s)/(2-10s) & G2 = (2-10s)/ (2 +10s) but than I read that all poles and zeroes should be inside the unit circle, and I don't know how to move the Zero S_01 = 1 to the unit circle
  2. binis

    A How is phase velocity related to deflection angle?

    Refractive index is a function of velocity in the medium. How is this related to deviation angle inside the medium? I am not asking for the known formula, but for the mechanism behind it.
  3. doggy

    How to wire a house using 3 phase

    We are getting 3 phase power delivered to our property via our own dedicated transformer. We want to rewire the house and other buildings so that we can use different appliances on different phases. We have 4 air conditioners, 3 hot water units and the usual assortment of things you would find...
  4. Kaguro

    A Meaning of density of microstates in phase space

    Hello all. I am studying stat mech from Pathria's book. It says a system is completely described by all positions and momenta of all the N particles. This maybe represented by a single point in 6N-D gamma space. So, each point is a (micro)state. Now if we restrict the system (N,V,E to E+ΔE)...
  5. Y

    Does wire length difference create phase shift?

    When wiring a 240 volt AC circuit, I've always assumed that it's important for L1 and L2 wires to be the exact same length, in order to avoid introducing a phase shift that would reduce peak voltage. Length differences can accumulate when the wires enter a panel and need to go slightly...
  6. Iwanttolearnphysics

    What exactly happens during a phase change?

    What will happen if say, I have both ice and water inside the refrigerator and I set the fridge to exactly 0 degrees Celsius? Since both melting and freezing happen at 0 degrees, what will happen to my water? what about to my ice? Will they stay the same? I know this is an ignorant question, but...
  7. P

    I Notation of the approximation in quantum phase estimation algorithm

    I'am interested in the notation of the approximation in quantum phase estimation algorithm. In the literature there are different definitions, which I divide into two cases here. Both different in their definition of the ##\delta##. In both cases I start with a quote of the source and show an...
  8. ergospherical

    I How to Find the Berry Phase in Slowly Varying Systems

    I was trying to follow this page: https://phyx.readthedocs.io/en/latest/TI/Lecture notes/2.html With ##|n(\mathbf{R})\rangle## being the eigenstates of ##H|\mathbf{R} \rangle## of eigenvalue ##E_n(\mathbf{R})##, the task is to solve the Schroedinger equation ##i | \dot{\psi}(t) \rangle =...
  9. Butterfly41398

    Three phase total power consumed

    Summary:: I don't seem to see any problem with my work. But my final answer does not match the correct answer. (In number 3) Here's my work
  10. P

    I Quantum phase estimation - Question regarding rewriting the state

    In Nielsen and Chuang p.223 we have the following situation: $$\frac{1}{2^t} \sum\limits_{k,l=0}^{2^t-1} e^{\frac{-2\pi i k l}{2^t}} e^{2 \pi i \varphi k} |l\rangle$$ Which results from applying the inverse quantum Fourier transform to state ##\frac{1}{2^{t/2}} \sum\limits_{k=0}^{2^t-1}...
  11. M

    A HHL quantum algorithm and the phase estimation

    In HHL algorithm, does the controlled unitary (Hamiltonian simulation part of Quantum phase estimation) depend on Hermitian matrix coefficients and how?
  12. casualguitar

    Modelling of two phase flow in packed bed using conservation equations

    Previously, I have seen the derivation of the energy conservation equations for simulation of single phase flow in a porous media (a packed bed). These are the energy equations for the solid and fluid respectively: I understand the derivation, however, these equations will only work when the...
  13. dRic2

    Time dependent perturbation theory (Berry phase)

    If I plug the solution into the Schrodinger equation I get $$(i \hbar \partial_t - H)\ket{\psi} = 0$$ Since I know that the zeroth-order expansion is lambda is already a solution I think this is equal to $$(i \hbar \partial_t - H)e^{i\phi} e^{-i\gamma}\ket{\delta n} = 0$$ If now I carry on with...
  14. S

    Mathematica Adapting Unwrapping Techniques for Plotting Phase Values

    This discussion https://community.wolfram.com/groups/-/m/t/1340126 includes some ideas to unwrap a list of wrapped-around values such as phase (e.g. Arg[ f[N] ] ). You can use this to ListPlot a jump-free graph. I'm trying to adapt this to work in Plot rather than ListPlot. The idea is to plot...
  15. P

    I Measurement of a qubit in the computational basis - Phase estimation

    Hello, I have a question about the measurement of a qubit in the computational basis. I would like to first state what I know so far and then ask my actual question at the end.What I know: Let's say we have a qubit in the general state of ##|\psi\rangle = \alpha|0\rangle + \beta|1\rangle##. Now...
  16. D

    I Physical interpretation of phase in solutions to Schrodinger's Eqn?

    Hello all, So I've been working through the solutions to some simple introductory problems for the Schrodinger Equation like the infinite square well, and I'm trying to make sense of how to think about the phase component. For simplicity's sake, let's start off by assuming we've measured an...
  17. U

    I Phase Speed of Wave in non-relativistic Doppler Shift Derivation

    Consider the situation where an observer at rest on the ground measures the frequency of a siren which is moving away from the observer at speed ##v_{Ex}##. Let ##v_w## be the speed of the sound wave. Let ##\lambda_0##, ##f_0##, ##\lambda_D##, and ##f_D## be the wavelengths and frequencies...
  18. S

    C/C++ How can phase singularities be implemented in C++?

    hello i would like to ask how to implement phase singularities in C++. thanks very much.
  19. S

    Adding two sinusoidal waves of same frequency but out of phase

    Asin(wt)}+Bsin(wt+a) Asin(wt) +B sin(wt)cos(a) +Bcos(wt)sin(a) Asin(wt) + ksin(wt) + Lcos( wt) (A+K) sin(wt) + Lcos(wt) Fsin(wt) + Lcos(wt)
  20. N

    A What are the methods for calculating quantum phase transition?

    Trying to understand what the math methods are exist to determine quantum phase transition and how I can calculate it, by what methods.
  21. P

    A Phase diagram of Carbon at large electric fields.

    I am wondering if the phase diagram of Carbon has been explored at very large electric fields. Can one make any theoretical guesses ? In specific I am interested in Pressure Vs Electric field and Electric field vs Temperature at fixed temperature and pressure respectively.
  22. raisins

    I Phase space integral in noninteracting dipole system

    Hi all, Consider a system of ##N## noninteracting, identical electric point dipoles (dipole moment ##\vec{\mu}##) subjected to an external field ##\vec{E}=E\hat{z}##. The Lagrangian for this system is...
  23. D

    How Do Engineers Design AntiNoise to Effectively Reduce Ambient Noise?

    Summary:: AmbientNoise + AntiNoise combined calculation I am having trouble with this question: Noise cancelling headphones use both passive (insulated earphones) and active (electronic “anti-noise”) methods to nullify ambient noise. One task of a sound engineer is to design low-energy...
  24. S

    I Explaining Quantum States: Global Phase

    I was teaching the basics of quantum states and was showing the students that an arbitrary state in a quantum two-level system could be written as ##|\psi\rangle = C_1 |+\rangle + C_2 |-\rangle = R_1 |+\rangle + R_2 e^{i \alpha} |-\rangle##, with {##C_i##} complex and {##R_i##} real. Then...
  25. D

    I Orbital distance increase during the white dwarf phase of the Sun

    Some estimates through calculating the sun mass loss and increase in mass loss say that the white dwarf phase of the Sun will have roughly about 50% the current mass of the Sun (not sure about it). Whatever the actual mass loss is going to be, assuming that the 50% mass loss is true, where would...
  26. M

    I Dependency of phase space generator to differential distributions

    I attatched an example plot where I created the histogram for the differential distribution with respect to the energy of the d-quark produced in the scattering process. My conception is that the phase space generator can "decide" how much of the available energy it assigns to the respective...
  27. C

    Purely passive RC Phase Shift Oscillator?

    It is possible to build a purely passive RC phase shift oscillator with 2 separate (in the future) RC stages like this? Where there would be 2 RC networks that each provide 180 degrees of phase shift. Of course, there would be a buffer in between the 2 RC networks so that they behave as 2...
  28. P

    3 Phase Harmonics and Solid State Relay Issues

    I have a 3 phase problem that I think might be applicable to this forum. The setup is equipment which contains 5 resistive heaters (A through E). The unit is powered by 208V 3 phase and each of the heaters are hooked up line to line in an unbalanced configuration as follows: L1-L2: Heater D...
  29. B

    I How to recalculate Berry phase dipole moments (jumps over time)?

    Is there anyone out there who can help a newbie understand how to deal with Berry phase dipole moment data? I ran a simulation to calculate dipole moments over time using the Berry phase method. The problem is that there are jumps in my data. There is an example at the end of this post (part...
  30. S

    A Berry phase in condensed matter

    I am trying to understand how is topology used to characterize materials. So I understand that to calculate the Berry phase you will parameterize your Hamiltonian and change this parameter in some way and return to the initial value. What I do not understand is what does this changing of...
  31. baby_1

    Phase velocity in oblique Angle propagation (Plane wave)

    Hello, Regarding the wave oblique angle propagation and based on Balanis "Advanced engineering Electromagnetic" book on page 136 ( it has been attached) I need to know why the phase velocity in x direction is not important to keep in step with a constant phase plane( Just equation 4-23). I...
  32. R

    Design a linear phase low pass filter

    Design a linear phase low pass filter whose specification is:1) Maximum tolerance in the passband equal to 0.01% (linear) in the passband;2) Cutoff frequency at ω_c = 0.3π and transition band at 0.05π;3) Minimum reduction of the 0.95 rejection band.
  33. S

    I How Do You Calculate Day-Specific Phase Shifts in Excel for Sine Waves?

    Hi, I have created a sine wave with the following options: 1.) - changing the period/length in days of the sine wave (Cycle Length in Days) 2.) - calculating the start value of the "dummy" so that the sine wave always starts with -1 (Dummy Start at Cycle Trough) when the phase shift is set...
  34. baby_1

    Attenuation and Phase constant values in wave equation

    Regarding wave equation we are faced with this form $$\nabla^2 \vec{E}=j\omega \mu \sigma \vec{E}-j\omega \mu\varepsilon \vec{E}=\gamma ^2\vec{E}$$ where $$\gamma ^2=j\omega \mu \sigma -j\omega \mu\varepsilon $$ $$\gamma =\alpha +j\beta $$ where alpha and beta are attenuation and phase...
  35. D

    B Is Mean Temp in 2 phase Heat Exchangers Higher Than Logarithmic Mean?

    Is Mean Temp in 2 phase Heat Exchangers Higher Than Logarithmic Mean? I am looking at this paper: https://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1314&context=iracc Having a bit of trouble understanding all of it, but my basic question is just: If I have a heat pump where the hot...
  36. I

    Help Plotting Phase Difference using LTSpice please

    How do i plot phase difference in a Ltspice in this circuit ?
  37. RicardoMP

    A How to reduce an integral in phase space to a one-dimensional form?

    I've been trying for a very long time to show that the following integral: $$ I_D=2{\displaystyle \int} \, {\displaystyle \prod_{i=1}^3} d \Pi_i \, (2\pi )^4\delta^4(p_H-p_L-p_R) |{\cal M}({e_L}^c e_R \leftrightarrow h^*)|^2 f_{L}^0f_{R}^0(1+f_{H}^0). $$ can be reduced to one dimension: $$ I_D...
  38. C

    RC Phase Shift Oscillator not Oscillating

    Hello everyone. I am having some trouble with an RC phase shift oscillator that I built as a hobby project. I am completely stuck on this and I just cannot figure it out. My oscillator is not oscillating. Here is the circuit that I am trying to get to work. Taken from...
  39. oscarrod5

    Exploring Phase Potential Difference in 3-Phase Power

    I understand phase voltage (phase to neutral) well, but I'm still confused by what exactly the potential difference is between any 2 phases in 3 phase power. If you were to try to find the potential difference where 2 sine wave phases cross, then at that instantaneous point, the potential...
  40. M

    Standing waves between two speakers in phase

    The solution provided in the manual poses that the point halfway between the nodes at each speaker is an antinode of pressure (node of displacement) but isn't that a contradiction to the fact that the speakers are in phase? My first thought was that they must interfere constructively and have...
  41. A

    Metering a Single Phase 208 VAC Circuit

    Good day, I hope to understand how to use a 3 phase energy meter to measure single phase 208 VAC circuit. The basic idea seems simple, yet, complex meters don't seem to have this ability. Would anyone be able to describe what kind of information one would need from a digital 3 phase meter...
  42. I

    Chemistry Why does evaporating water cause some water to be cooled and form ice?

    Answer: I know that when water evaporates, it absorbs heat, that's why the process is endothermic. I don't understand why the water would be cooled and some ice would form, when the water is supposed to evaporate. What causes some water to be separately cooled instead of evaporated? Thanks.
  43. R

    180 degree phase shift of reflected light

    When light originating from a medium of lower refractive index reflects off a surface of higher refractive index, why does the phase shift by 180 degrees? Stokes relations show that reflection coefficients at the surface are equal but of opposite signs depending on direction of light (i.e...
  44. dvscrobe

    Aliasing Phase Shift: Determining Phase Shift

    How do you determine the phase shift of an aliased signal?
  45. PHYSICSKOP

    I Undamped driven oscillation — Is there a phase delay?

    I know that there is phase delay in damped driven oscillation but I want to know is there any phase delay in undamped driven oscillation when we apply sinusoidal driving force. When driving force is maximum, displacement is also maximum as well right?
  46. adamaero

    Engineering How to calculate rotor flux of the three phase squirrel cage induction motor?

    Three phase squirrel cage induction motor with given parameters (stator winding connected in delta) nominal power: Pn=22.4kW nominal stator voltage: Vsn=230V nominal stator current: Isn=39.5A nominal stator frequency: fsn=60Hz nominal speed: nn=1168min−1 number of pole pairs: 3 stator...
  47. AHSAN MUJTABA

    A Phase Portraits of a system of differential equations

    One thing that bothers me regarding the phase portraits, if I plot a phase portrait, then all my possible solutions (for different initial conditions) are included in the diagram? In other words, a phase portrait of a system of ODE's is its characteristic diagram?
  48. tworitdash

    MATLAB How to change the frequency values inside a time domain signal phase

    The problem I am having is simple. I have a Gaussian spectrum initially. Like this, Process 1: S = m0/sqrt(2*pi*sigma^2) * exp(-(vel_axis - mu).^2/(2*sigma^2)); Here, mu is the mean velocity (frequency) and sigma is the standard deviation. vel_axis is the axis on which I am calculating this...
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