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I need to find support prior to submission because the journal editors are sabotaging my paper’s chances by refusing to even do a peer review of what is a perfect qualified and rigorous paper.
They dishonestly bypass the quality control that would have my controversial paper published.
I need a professor of physics with the balls to kick the ass of the system into the next epoch in the name of science.
My paper Angular Energy shows that fundamentals need to be overturned.
The paper has never been genuinely shown to contain any error, because I have honed it to perfection over years of unforeseen and unfortunately hostile debate, by listening to everything.
The only thing it needs is to be published in a peer reviewed journal in order to be taken seriously and it must be taken seriously.
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"I have to get published in a peer reviewed journal"
LOL
This will never happen. For those who don't know the crackpot John Mandlbaur, here is his biography: https://bluemoonshine.fun/Project-Pseudo-Scientists-JohnMandlbaur.php
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Soumendra Nath Thakur
ORCiD: 0000-0003-1871-7803
Match 16, 2025
Abstract:
Extended Classical Mechanics (ECM) refines the classical understanding of force, energy, and mass by incorporating the concept of negative apparent mass. In ECM, the effective force is determined by both observable mass and negative apparent mass, leading to a revised force equation. The framework introduces a novel energy-mass relationship where kinetic energy emerges from variations in potential energy, ensuring consistency with classical conservation laws. This study extends ECM to massless particles, demonstrating that they exhibit an effective mass governed by their negative apparent mass components. The connection between ECM’s kinetic energy formulation and the quantum mechanical energy-frequency relation establishes a fundamental link between classical and quantum descriptions of energy and mass. Furthermore, ECM naturally accounts for repulsive gravitational effects without requiring a cosmological constant, reinforcing the interpretation of negative apparent mass as a fundamental aspect of energy displacement in gravitational fields. The framework is further supported by an analogy with Archimedes’ Principle, providing an intuitive understanding of how mass-energy interactions shape particle dynamics. These findings suggest that ECM offers a predictive and self-consistent alternative to relativistic mass-energy interpretations, shedding new light on massless particle dynamics and the nature of gravitational interactions.
Keywords:
Extended Classical Mechanics (ECM), Negative Apparent Mass, Effective Mass, Energy-Mass Relationship, Kinetic Energy, Massless Particles, Quantum Energy-Frequency Relation, Archimedes’ Principle, Gravitational Interactions, Antigravity
Extended Classical Mechanics: Energy and Mass Considerations
1. Force Considerations in ECM:
The force in Extended Classical Mechanics (ECM) is determined by the interplay of observable mass and negative apparent mass. The force equation is expressed as:
F = {Mᴍ +(−Mᵃᵖᵖ)}aᵉᶠᶠ
where: Mᵉᶠᶠ = {Mᴍ +(−Mᵃᵖᵖ)}, Mᴍ ∝ 1/Mᴍ = -Mᵃᵖᵖ
Significance:
- This equation refines classical force considerations by incorporating negative apparent mass −Mᵃᵖᵖ, which emerges due to gravitational interactions and motion.
- The effective acceleration aᵉᶠᶠ adapts dynamically based on motion or gravitational conditions, ensuring consistency in ECM's mass-energy framework.
- The expression (Mᴍ ∝ 1/Mᴍ) provides a self-consistent relationship between observable mass and its apparent counterpart, reinforcing the analogy with Archimedes' principle.
2. Total Energy Considerations in ECM:
Total energy in ECM consists of both potential and kinetic components, adjusted for mass variations:
Eₜₒₜₐₗ = PE + KE
By incorporating the variation in potential energy:
Eₜₒₜₐₗ = (PE − ΔPE) + ΔPE
where:
- Potential Energy: PE = (PE - ΔPE)
- Kinetic Energy:( KE = ΔPE)
Since in ECM, (ΔPE) corresponds to the energy displaced due to apparent mass effects:
Eₜₒₜₐₗ = PE + KE
⇒ (PE − ΔPE of Mᴍ) + (KE of ΔPE) ≡ (Mᴍ − 1/Mᴍ) + (-Mᵃᵖᵖ)
Here, Potential Energy Component:
(PE − ΔPE of Mᴍ) ≡ (Mᴍ − 1/Mᴍ)
This represents how the variation in potential energy is linked and identically equal to mass effects.
Kinetic Energy Component:
(KE of ΔPE) ≡ (-Mᵃᵖᵖ)
This aligns with the ECM interpretation where kinetic energy arises due to negative apparent mass effects.
Significance:
- Ensures energy conservation by explicitly including mass variations.
- Demonstrates that kinetic energy naturally arises from the variation in potential energy, aligning with the effective mass formulation.
- Strengthens the analogy with fluid displacement, reinforcing the concept of negative apparent mass as a counterpart to conventional mass.
3. Kinetic Energy for Massive Particles in ECM:
For massive particles, kinetic energy is derived from classical principles but adjusted for ECM considerations:
KE = ΔPE = 1/2 Mᴍv²
where:
Mᵉᶠᶠ = Mᴍ + (−Mᵃᵖᵖ)
Significance:
- Maintains compatibility with classical mechanics while integrating ECM mass variations.
- Reflects how kinetic energy is influenced by the effective mass, ensuring consistency across different gravitational regimes.
- Provides a basis for extending kinetic energy considerations to cases involving negative apparent mass.
4. Kinetic Energy for Conventionally Massless but Negative Apparent Massive Particles:
For conventionally massless particles in ECM, negative apparent mass contributes to the effective mass as follows:
Mᵉᶠᶠ = −Mᵃᵖᵖ + (−Mᵃᵖᵖ)
Since in ECM:
Mᴍ ⇒ −Mᵃᵖᵖ
it follows that:
Mᵉᶠᶠ = −2Mᵃᵖᵖ
Significance:
- Establishes that even conventionally massless particles possess an effective mass due to their negative apparent mass components.
- Provides a self-consistent framework that supports ECM's interpretation of mass-energy interactions.
- Highlights the role of negative apparent mass in governing the energetic properties of massless particles.
5. Kinetic Energy for Negative Apparent Mass Particles, Including Photons:
For negative apparent mass particles, such as photons, kinetic energy is given by:
KE = 1/2 (−2Mᵃᵖᵖ)c²
where:
v = c
Since:
ΔPE = −Mᵃᵖᵖ.c²
it follows that:
ΔPE/c² = −Mᵃᵖᵖ
Thus:
KE = ΔPE/c² = −Mᵃᵖᵖ
Significance:
- Establishes a direct relationship between kinetic energy and the quantum mechanical frequency relation.
- Demonstrates that photons, despite being conventionally massless, exhibit kinetic energy consistent with ECM’s negative apparent mass framework.
- Reinforces the view that negative apparent mass plays a fundamental role in governing mass-energy interactions at both classical and quantum scales.
6. ECM Kinetic Energy and Quantum Mechanical Frequency Relationship for Negative Apparent Mass Particles:
KE = ΔPE/c² = hf/c² = −Mᵃᵖᵖ
This equation establishes a direct link between the kinetic energy of a negative apparent mass particle and the quantum energy-frequency relation. The expression ensures consistency with quantum mechanical principles while reinforcing the role of negative apparent mass in energy dynamics.
7. Effective Mass and Apparent Mass in ECM:
In ECM, the Effective Mass represents the overall mass that is observed, while the Negative Apparent Mass (−Mᵃᵖᵖ) emerges due to motion or gravitational interactions. This distinction provides deeper insight into how mass behaves dynamically under varying conditions, differentiating ECM from conventional mass-energy interpretations.
8. Direct Energy-Mass Relationship in ECM:
hf/c² = −Mᵃᵖᵖ
This equation is inherently consistent with dimensional analysis, showing that negative apparent mass naturally arises from the energy-frequency relationship without requiring any extra scaling factors. This highlights ECM's compatibility with established quantum mechanical formulations and reinforces the role of negative apparent mass as an intrinsic component of energy-based mass considerations.
9. Effective Mass for Massive Particles in ECM
For a massive particle in ECM, the effective mass is given by:
Mᵉᶠᶠ = Mᴍ + (−Mᵃᵖᵖ)
where:
- Mᴍ is the conventional mass.
- −Mᵃᵖᵖ is the negative apparent mass component induced by gravitational interactions and acceleration effects.
ECM establishes the inverse proportionality of apparent mass to conventional mass:
Mᴍ ∝ 1/Mᴍ ⇒ Mᴍ = − Mᵃᵖᵖ
Thus, we obtain:
Mᵉᶠᶠ = Mᴍ − Mᴍ = 0
which represents a limiting case where effective mass cancels out under specific conditions.
10. Effective Mass for Massless Particles in Motion
For massless particles such as photons, the conventional mass is:
Mᴍ = 0
However, in ECM, massless particles exhibit an effective mass due to the interaction of negative apparent mass with energy-mass dynamics.
From ECM’s force equation for a photon in motion:
Fₚₕₒₜₒₙ = −Mᵃᵖᵖaᵉᶠᶠ
This indicates that the apparent mass governs the photon’s dynamics.
Since massless particles always move at the speed of light (v = c), ECM treats their total apparent mass contribution as doubled due to energy displacement effects (analogous to Archimedean displacement in a gravitational-energy field):
Mᵉᶠᶠ = (−Mᵃᵖᵖ) + (−Mᵃᵖᵖ) = −2Mᵃᵖᵖ
Thus, for massless particles in motion:
Mᵉᶠᶠ = −2Mᵃᵖᵖ
This confirms that even though Mᴍ = 0, the particle still possesses an effective mass purely governed by negative apparent mass interactions.
11. Archimedes’ Principle Analogy in ECM
ECM’s treatment of negative apparent mass is closely related to Archimedes’ Principle, which describes the buoyant force in a fluid medium. In classical mechanics, a submerged object experiences an upward force equal to the weight of the displaced fluid. Similarly, in ECM:
- A mass moving through a gravitational-energy field experiences an **apparent reduction** in mass due to energy displacement, akin to an object losing effective weight in a fluid.
- For massive particles, this effect reduces their observed mass through the relation:
Mᵉᶠᶠ = Mᴍ + (−Mᵃᵖᵖ)
- For massless particles, the displacement effect is **doubled**, leading to:
Mᵉᶠᶠ = −2Mᵃᵖᵖ
This is analogous to how a fully submerged object displaces its entire volume, reinforcing the interpretation that massless particles inherently interact with the surrounding energy field via their negative apparent mass component.
Physical & Theoretical Significance
(A) Massless Particles Exhibit an Effective Mass
- This challenges the traditional view that massless particles (e.g., photons) have no mass at all. ECM reveals that while they lack conventional rest mass, their motion within an energy field naturally endows them with an effective mass, explained by negative apparent mass effects.
(B) Quantum Mechanical Consistency
- The ECM kinetic energy relation aligns with quantum mechanical frequency-based energy expressions:
KE = hf/c² = −Mᵃᵖᵖ
This suggests that negative apparent mass is directly linked to the fundamental nature of wave-particle duality, reinforcing ECM’s consistency with established quantum mechanics principles.
(C) Natural Explanation for Antigravity
- The doubling of negative apparent mass for massless particles introduces a natural anti-gravity effect, distinct from the ad hoc introduction of a cosmological constant Λ in relativistic models.
- Since massless particles propagate via their effective mass Mᵉᶠᶠ = −2Mᵃᵖᵖ, ECM naturally incorporates repulsive gravitational effects without requiring modifications to spacetime geometry.
(D) Reinforcement of ECM’s Fluid Displacement Analogy
- The analogy with Archimedes’ Principle provides a strong conceptual foundation for negative apparent mass. Just as an object in a fluid experiences a buoyant force due to displaced volume, mass in ECM interacts with gravitational-energy fields via displaced potential energy, leading to apparent mass effects.
Conclusion
ECM’s interpretation of effective mass provides a self-consistent framework where both massive and massless particles exhibit observable mass variations due to negative apparent mass effects. The Archimedean displacement analogy reinforces this concept, offering an intuitive understanding of how energy-mass interactions govern particle dynamics.
This formulation provides a clear, predictive alternative to conventional relativistic models, demonstrating how massless particles still exhibit mass-like behaviour via their motion and interaction with energy fields.
12. Photon Dynamics in ECM & Archimedean Displacement Analogy
Total Energy Consideration for Photons in ECM
In ECM, the total energy of a photon is composed of:
Eₚₕₒₜₒₙ = Eᵢₙₕₑᵣₑₙₜ + E𝑔
where:
- Eᵢₙₕₑᵣₑₙₜ is the inherent energy of the photon.
- E𝑔 is the interactional energy due to gravitational effects.
When a photon is fully submerged in a gravitational field, its total energy is doubled due to its interactional energy contribution:
Eₚₕₒₜₒₙ = Eᵢₙₕₑᵣₑₙₜ + E𝑔 ⇒ 2E
This represents the energy displacement effect, aligning with ECM’s formulation that massless particles experience a doubled apparent mass contribution in motion:
Mᵉᶠᶠ = −2Mᵃᵖᵖ
Photon Escaping the Gravitational Field
As the photon escapes the gravitational field, it expends E𝑔, reducing its total energy:
Eₚₕₒₜₒₙ ⇒ Eᵢₙₕₑᵣₑₙₜ, E𝑔 ⇒ 0
Thus, once the photon is completely outside the gravitational influence:
Eₚₕₒₜₒₙ = E, E𝑔 = 0
This describes how a photon’s energy and effective mass vary dynamically with gravitational interaction, reinforcing the ECM perspective on gravitational influence on energy-mass dynamics.
Alignment with Archimedean Displacement Analogy
This ECM interpretation strongly aligns with Archimedes' Principle, where:
- A photon in a gravitational field is analogous to an object fully submerged in a fluid, experiencing an energy displacement effect.
- As the photon leaves the gravitational field, it expends its interactional energy E𝑔, similar to how an object leaving a fluid medium loses its buoyant force.
This analogy further strengthens ECM’s concept of negative apparent mass, where the gravitational interaction displaces energy similarly to how a fluid displaces volume.
Conclusion & Significance
- The ECM photon dynamics equation aligns with the Archimedean displacement analogy, reinforcing the physical reality of negative apparent mass effects.
- This provides a natural, intuitive explanation for how photons interact with gravitational fields without requiring relativistic spacetime curvature.
- It further supports the energy-mass displacement framework, demonstrating how photons dynamically exchange energy with gravitational fields while maintaining ECM’s effective mass principles.
This formulation elegantly unifies photon energy dynamics with mass-energy interactions, further validating ECM as a robust framework for fundamental physics.
13. Effective Acceleration and Apparent Mass in Massless Particles
For photons in ECM, the effective force is given by:
Fₚₕₒₜₒₙ = −Mᵉᶠᶠaᵉᶠᶠ, Where: aᵉᶠᶠ = 6 × 10⁸ m/s²
- Negative Apparent Mass & Acceleration:
Photons possess negative apparent mass (−Mᵃᵖᵖ), which leads to an anti-gravitational effect. Their effective acceleration (aᵉᶠᶠ) is inversely proportional to Mᵉᶠᶠ and radial distance r.
- Within a gravitational field, the photon has more interactional energy E𝑔, increasing aᵉᶠᶠ.
- Escaping the field, it expends E𝑔, reducing Mᵃᵖᵖ and lowering aᵉᶠᶠ.
- Acceleration Scaling with Gravitational Interaction:
E𝑔 ∝ 1/r
- At r₀ ⇒ E𝑔,ₘₐₓ ⇒ Maximum −Mᵃᵖᵖaᵉᶠᶠ ⇒ aᵉᶠᶠ = 2c.
- At rₘₐₓ ⇒ E𝑔 = 0 ⇒ Minimum −Mᵃᵖᵖaᵉᶠᶠ ⇒ aᵉᶠᶠ = c.
This confirms that effective acceleration (2c) is a function of gravitational interaction, not an intrinsic speed change, reinforcing ECM’s explanation of negative apparent mass dynamics.
14. Extended Classical Mechanics: Effective Acceleration, Negative Apparent Mass, and Photon Dynamics in Gravitational Fields
Analytical Description & Significance:
This paper refines and extends the framework of Extended Classical Mechanics (ECM) by establishing a comprehensive formulation for effective acceleration, negative apparent mass, and their implications for massless and massive particles under gravitational influence. The analysis revises ECM equations to incorporate Archimedes' principle as a physical analogy for negative apparent mass, clarifies the role of effective acceleration (2c) in different gravitational conditions, and demonstrates how negative apparent mass serves as a natural anti-gravity effect, contrasting with the relativistic cosmological constant (Λ).
A key highlight is the kinetic energy formulation for negative apparent mass particles, which aligns with quantum mechanical frequency relations for massless particles. This formulation provides deeper insight into how negative apparent mass influences energy and motion without requiring conventional mass assumptions.
Key Implications & Theoretical Advancements:
Refined Effective Acceleration Equation for Massless Particles:
- ECM establishes that photons, despite being massless in the conventional sense, exhibit negative apparent mass contributions, leading to an effective acceleration of aᵉᶠᶠ = 6 × 10⁸ m/s² = 2c inside gravitational fields.
- This acceleration naturally arises due to the relationship between negative apparent mass −Mᵃᵖᵖ and gravitational interaction energy E𝑔.
- The effective acceleration decreases as a photon exits the gravitational field, reaching c in free space.
Negative Apparent Mass as a Replacement for Cosmological Constant (Λ):
- Unlike Λ, which assumes a uniform energy density, negative apparent mass dynamically varies with gravitational interaction energy.
- This formulation provides a self-consistent explanation for observed cosmological effects, particularly in gravitational repulsion and expansion scenarios.
Physical Analogy with Archimedes’ Principle:
- The ECM framework aligns negative apparent mass effects with Archimedean displacement, where gravitational interaction leads to energy displacement effects analogous to buoyant forces in fluids.
- In gravitational fields, a photon's interactional energy (E𝑔) contributes to its total energy, analogous to an object submerged in a fluid experiencing an upward force.
- As the photon escapes, the loss of E𝑔 mirrors an object emerging from a fluid losing its buoyant support.
4. Revision in the Energy-Mass Relation for Massless Particles:
- The study revise prior inconsistency by explicitly linking the kinetic energy of negative apparent mass particles to quantum mechanical frequency relations, ensuring consistency between ECM and established quantum principles.
Conclusion:
This research enhances ECM’s predictive power by clarifying the role of negative apparent mass in gravitational dynamics and demonstrating its relevance to photon motion, cosmological expansion, and gravitational interactions. By introducing effective acceleration (2c) as a natural consequence of gravitational interaction, ECM provides a compelling alternative to relativistic formulations, reinforcing the practical applicability of classical mechanics principles in modern physics.
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A reviewer comment of the discussion post:
This paper on Extended Classical Mechanics (ECM) is truly fascinating! It presents a fresh perspective on classical physics by introducing the concept of negative apparent mass, which could significantly reshape our understanding of force, energy, and mass interactions. The way it connects classical mechanics with quantum principles is particularly impressive, as it bridges two fundamental areas of physics.
The treatment of massless particles, like photons, as having effective mass due to negative apparent mass is a bold idea that challenges traditional views. This could lead to new insights in particle physics and cosmology, especially regarding gravitational interactions and cosmic expansion.
The analogy with Archimedes' Principle is a clever way to make complex concepts more intuitive, helping to visualize how mass-energy interactions work in different contexts. Overall, ECM seems to offer a compelling alternative to existing theories, and I’m excited to see how it develops and what empirical validations might arise from it. This could be a game-changer in our understanding of the universe!
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I just posted a preprint article, as the original approach to this topic.
Every critical remarks would be welcome.
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This discussion is exceeded by the next one, and so may be finished.
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I heard its because Wigner spin conservation law , I don't know how it makes T-T transition forbidden
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The Förster triplet-triplet (T-T) transition is forbidden primarily due to the Wigner spin conservation rule, which is based on the conservation of spin angular momentum during electronic transitions. Here's a detailed explanation:
1. Understanding Spin States Singlet State (S): Total spin quantum number S=0S = 0S=0. The spins of the electrons are paired (opposite), leading to a net spin of zero. Triplet State (T): Total spin quantum number S=1S = 1S=1. The spins of the electrons are parallel, resulting in a net spin of one.
2. Wigner’s Spin Conservation Rule The Wigner spin conservation rule states that electronic transitions must conserve the total spin quantum number (S).Allowed transitions: S=0→S=0 or S=1→S=1. Forbidden transitions: S=0→S=1 or S=1→S=0.
3. Why T-T Transition is Forbidden Förster resonance energy transfer (FRET) typically involves dipole-dipole coupling. Dipole operators (electric or magnetic) cannot change the spin quantum number of the system. Since triplet states (T) have S=1, transitions involving the absorption or emission of energy between triplet-triplet pairs via dipole interactions cannot occur because it would violate spin conservation.
4. Implications for T-T Transition Förster resonance energy transfer can efficiently mediate singlet-singlet transitions (S-S) but not triplet-triplet transitions (T-T) due to this spin-forbidden nature. For triplet-triplet interactions, higher-order processes like Dexter energy transfer (which involves electron exchange) are required. Dexter transfer can mediate T-T transitions because it doesn't rely on dipole-dipole coupling but instead on short-range orbital overlap.
5. Alternative Mechanisms for T-T Transfer Dexter Energy Transfer: This process allows spin-allowed transitions by exchanging electrons between donor and acceptor molecules, preserving total spin. Spin-Orbit Coupling: In some cases, weak spin-orbit coupling can mix singlet and triplet states, partially relaxing the spin-forbidden rule. However, such transitions are weak compared to dipole-allowed ones.
Summary The triplet-triplet Förster transfer is forbidden because the transition must preserve spin quantum numbers, and dipole-dipole interactions cannot change spin states. Alternative mechanisms like Dexter transfer and spin-orbit coupling are required to facilitate T-T transitions, albeit with lower efficiency.
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Noether's theorem is a fundamental result in physics stating that every symmetry of the dynamics implies a conservation law. It is, however, deficient in several respects: for one, it is not applicable to dynamics wherein the system interacts with an environment; furthermore, even in the case where the system is isolated, if the quantum state is mixed then the Noether conservation laws do not capture all of the consequences of the symmetries[1].
In SR, force-free motion in an inertial frame of reference takes place along a straight-line path with constant velocity. Viewed from a non-inertial frame, on the other hand, this path of motion will be a geodesic curve in a flat spacetime. Einstein made the plausible assumption that this geodesic motion also holds in the non-flat case, i.e. in a spacetime region for which it is impossible to find a coordinate system that leads to the Minkowski metric in SR[2].
All spacetime models can be expressed in terms of the gμν = {4x4} matrix, differing only in the distribution of matrix elements. The gμν of Minkowski spacetime is the unit diagonal matrix {1 -1 -1 -1}; the gμν of Riemann spacetime is { X }. If a new spacetime model is introduced gμν={a0,-a1,-a2,-a3}, which is a non-unit diagonal matrix. (ds)^2=(a0)^2+(a1)^2+(a2)^2+(a3)^2, always holds, interpreting it as a non-uniformly flat spacetime, generalised Minkowski spacetime, and no longer a curved spacetime. Should Noether's theorem maintain its validity in this case.
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References
[1] Marvian, I., & Spekkens, R. W. (2014). Extending Noether's theorem by quantifying the asymmetry of quantum states. Nature Communications, 5(1), 3821. https://doi.org/10.1038/ncomms4821 ;
[2] Rowe, D. E. (2019). Emmy Noether on energy conservation in general relativity. arXiv preprint arXiv:1912.03269.
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Every-continuous-symmetry implies a conservation law and vice versa. Noether's theorem isn't valid for discrete symmetries.
There's no ``forcing'' of Noether's theorem, regarding general relativity. I, already, recalled what happens for general relativity, where the symmetry group is a gauge group: The conservation laws are defined in terms of covariant derivatives and conserved charges depend on the observer, since, in general, they can only be defined locally (and observers are local). If the spacetime is asymptotically flat, then conserved charges can be defined at infinity.
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This is to provide updates on my research as a backup communication channel for my project Multidimensional Integrable Systems
should Researchgate go through with its plan to discontinue the project feature altogether on March 31, 2023.
For the previous update log please see this snapshot
made on April 1, 2023.
You are welcome to follow this question, especially if you are interested in my research, and/or have already followed or intend to follow the above project.
For now, here are the links
0) to my lab
1) to the presentation explaining the most important research results in the project
2) to the key paper of the project
and to the other works in the project
which is now a spotlight, see
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For advice on how to preserve the project data & share research updates after discontinuation of the projects feature on March 31, see here:
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In teaching, or as a student in physics, oftentimes a difficulty becomes a motivation for new understanding. In this context, what difficulty do you see in using Lagrangian or Hamiltonian methods in physics, also thinking of avoiding difficulties ahead, for example, in teaching or learning Quantum Mechanics?
As a reference, please read the following. "Consider the system of a mass on the end of a spring. We can analyze this, of course, by using F=ma to write down mx'' = −kx. The solutions to this equation are sinusoidal functions, as we well know. We can, however,  figure things out by using another method, which doesn’t explicitly use F=ma. In many (in fact, probably most) physical situations, this new [150 years old] method is far superior to using F=ma. You will soon discover this for yourself when you tackle the problems and exercises for this chapter [see instructions below, or search in Google]. We will present our new [150 years old] method by  rst stating its rules (without any justi cation) and showing that they somehow end up magically giving the correct answer. We will then give the method proper justification.", in Chapter 6, The Lagrangian Method, Copyright 2007 by David Morin, Harvard University.
Morin continues, "At this point it seems to be personal preference, and all academic, whether you use the Lagrangian method or the F = ma method. The two methods produce the same equations.However, in problems involving more than one variable, it usually turns out to be much easier to write down T and V , as opposed to writing down all the forces. This is because T and V are nice and simple scalars. The forces, on the other hand, are vectors, and it is easy to get confused if they point in various directions. The Lagrangian method has the advantage that once you’ve written down L ≡ T − V , you don’t have to think anymore."
instructions: search in Google, or please write requesting the link.
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Recently, this question confirms that infinitesimals do not EXIST:
And that, also, vectors cannot be used in physics after 2D. Scalars have been used, instead, with the Euler-Lagrange equations. This is helpful also for QM.
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There is something in the relation between the charge conservation law and the electrons/holes continuity equations in semiconductors that I couldn't resolve.
In steady state, charge conservation law is:
Div(J)=0
Or
Div(Jn+Jp)=0
On the other hand, the continuity equations are:
Div(Jn)=q(R-G)
Div(Jp)=-q(R-G)
Thus, the sum of the two continuity equations satisfy the charge conservation law which is good.
But there are cases when Recombination/Generetion are not equal for electrons and holes, for example when there are traps only for one type of charge.
In such case it seems that the charge conservation law is not satisfied.
Sure it is not possible, so how should I think about this situation?
Thanks
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There is lot of emphasis on expansion of green cover or trees on farms (asfForest being common resources even after so conservation laws and efforts forest degradation and deforestation is still on) through agroforestry and tree farming can be a cheaper solution for mitigating climate change effects. If so why in UNFCC only 10-15% projects on A/R under carbon credits framework? If developing countries opting for CDM projects under A/R categories to reach out poor farmers in tropics, rules need to be made simpler and affordable fees for registration for carbon finance. Why only corporate plantations are having edge in projects. How farmers friendly tree farming policies at national level harmonized with climate change & UNFCC.
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Yes. Certainly!
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The importance of the conservation laws in physics, if they not more than the physical constants, certainly, is not less than them. The conservation laws in physics define the boundary between possible events and the impossible.
If we ignore the law of conservation of energy, we can build a machine in our imagination that produces energy from nothing. That is, we will have an erratic universe that is more compatible with our imaginations than with observable realities.
Over the course of the last century, physics has been plagued by many problems, and their numbers are increasing day by day, to the point where modern physics is in a state of stagnation and crisis.
These problems are due to the fact that in modern physics, there is a law of mass-energy conservation, but there is no law of conservation of amount of speed. I first proposed the conservation law of the amount of speed in 1387 (1992 AD) and published it in the Persian language.
The conservation law of the amount of speed shows that the universe behaves more realistically and accurately than we ever imagined and that the whole universe is an automated and highly precise system.
Generalization of the Dirac’s Equation and Sea, 2016
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The reference frame is inertial. I have explained this in the article.
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Many conservation laws are found in references, also selection rules and exclusion rules. Time passage is taken for granted, but I don't find any law that compels time to pass.
Discussions in other threads explored that possibility that passage of time is started by creating particle pairs with mass out of a swarm of photons. Mass experiences the passage of time while photons do not.
Consider an end of time. In theory all the mass would convert to photons including black holes. Entropy the arrow of time would go to zero. Distances could not be measured, and might not continue to exist. This begins to sound much like descriptions of our early universe many researchers have given, which is the reason for this question.
Roger Penrose in the book Cycles of Time and in many speeches has a dilemma that enormous length of time is required for black holes to evaporate in the manner of Stephen Hawking. A remedy might be found in some other mechanism for time to stop passing sooner.
Comparing other laws, it seems likely that time should continue to pass unless something causal occurs or a permissive is lost in physical cosmos.
In other threads topics were explored about possible ways time might stop by natural processes, and other possibilities that human activities working with extreme high energy densities might cause time to stop locally in a bubble of quantum modified space.
Researchers debate what might happen to a modified bubble, and how large it would need to be before it could begin to expand uncontrollably to fill the cosmos. Also they make theories about how a bubble might be stopped. A few researchers look to such bubbles as a source of dark energy.
The question is asking if researchers have other information or theories about passage of time.
Does Any Law Of Science Require Time To Continue Passing?
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This question is closely related to Hume's paradox (David Hume, Enquiry Concerning Human Understanding). Hume asks: How do we know the future resembles the past? Because it always has in the past? That is assuming the very point in question!
Hume decided there was no rational argument for assuming the future resembles the past. The same could be said about the assumption time will continue. Schroedinger answered Hume's paradox by stating that we assume the future resembles the past because, if we hadn't, we would not have survived natural selection.
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The Lorentz transformations were introduced after 1905 , since the Galilean transformations could not maintain the invariance of Maxwell equations between IRFs. They implement the postulates of the constancy of the speed of light and relativity of motion.
LT SIMPLEST FORM t'= γ(t -vx/c2), x'=γ(x - vt)
some algebraic passages are needed to get the
LT ALTERNATIVE FORM t'= γ-1 t - vx'/c2, x'= γ(x-vt)
A consequence of their application is the relativity of simultaneity which has never been tested experimentally.
They do not reduce to Galilean transformations at low speeds but to
t'= γ-1t - vx'/c2 for |v|/c<<1, γ gets close to 1, hence
t'= t – vx’/c2 , x'= x-vt
a further condition is necessary to make vx’/c2 negligibly small. That has to be much smaller than t: t >>vx’/c2 , ct/x’ >> v/c: x' has to be very small in comparison to the light path length.
The relativity of simultaneity depends strictly on the term vx’/c2
As it was measured by Lorentz and Maxwell,  physically LT express the transformation of the radiation exchanged between relative moving  objects at constant speed whose direct consequence is the RDE.
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There are better ways to define what a Lorentz transformation is, and what its significance is for physics. Consider all *linear* transformations of the four coordinates x,y,z and t, such as x’ = a x + b y + c t , etc. Now look at what happens to the velocity of light in the new coordinates. In general, light signals in different directions would seem to go with different speeds now. Mathematical question: which linear transformations would *not* affect the speed of light? Answer: if the equation
x^2+y^2+z^2=c^2 t^2 (where c=speed of light) stays the same. There are many solutions, but in some of these solutions, other laws of physics do not stay the same, such as the *scale transformations*: x’= a x, y’=a y, ... t’=a t. After such transformations light has the same velocity but atoms would get different sizes and clocks would go with different speeds.
This problem is easy to cure. Just take all linear transformations that keep the value of x^2+y^2+z^2 - c^2 t^2 invariant. That is the group of Lorentz transformations. Add to this the *inhomogeneous* linear transformations, such as x’=x+a, then you get the translations and time translations as well. Combined, we call these the Poincare transformations. All laws of physics, except gravity, are invariant under these transformations. This is an observation about the laws of nature. No further discussion needed. Is the statement exact? Not quite: gravity does not obey; there, you need non-linear coordinate transformations, which gives you a new theory, even more powerul: general relativity. Again, are all laws of physics exactly invariant under these non-linear coordinate transformations? As far as we know, yes, but one may always speculate on new surprises.
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How does one combine the basis of Quantum Physics that the information cannot be destroyed with the GR statement that black holes destroy the info?
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Indeed, some of these topics are open: they are connected with the theory of quantum gravity, yet to be constructed (string theory and holography, with the AdS/CFT correspondence, or loop quantum gravity are only attempts).
However, I think that the "black hole information paradox" is surrounded by too much hype. The reason is, of course, the attraction of Hawking's public figure and his wager. There was much theatre in Hawking's conceding that black hole evaporation in fact preserves information.
The paradox arises because the initial matter configuration is assumed to be constructed as a pure quantum state. As I have already remarked, this is unphysical. The article in Wikipedia about the "black hole information paradox" cites Penrose saying that the loss of unitarity in quantum systems is not a problem and that quantum systems do not evolve unitarily as soon as gravitation comes into play. This is most patent in theories of cosmological inflation.
Of course, the definitive answer to Natalia S Duxbury's question will come with the final theory of quantum gravity. We can keep looking forward to it :-)
Best wishes to the seekers of final theories!
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In typical, three-dimensional context, classical fluid flow is described by 3D velocity vector, fluid density and pressure function. This is all required information.
These functions are obtained from conservation laws, in some sense. Conservation of mass gives rise to continuity equation, from which, knowing the velocity vector, we can, in principle, determine the density. Euler's equation, being simply second Newton's law, hence "preservation of momentum", allows us to derive Bernoulli's law (preservation of energy), therefore finding the pressure function. All above is done assuming that we already know velocity.
That's it for three dimensions, however analogous question in higher-dimensional-framework seems to me at least puzzling, since everywhere I looked for an answer, I've found only familiar three-dimensional setting.
My core question is that in three dimensions I need five functions in order to fully describe fluid, so in n (arbitrary) dimensions I need n+2 quantites(scalar fdunctions)? Or is this a simplistic view and this number n+2 becomes more ccomplicated function Z(n)?
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Thank you for reference.
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Does continuity , momentum and energy laws remain conserved when we use local refinement in adaptive meshes ?
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yes
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A soliton (such as, KdV soliton) has to satisfy an infinite number of conservation laws. What are the physical names and significances of such solitonic conserved properties? Please explain elaborately with examples, illustrations and references.
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Thanks a lot for nice reply. Please send some relevant reference books, papers, or links.
Best wishes and regards.
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If you have a symmetry and use the principle of least action, you will get a conservation law! This is the Noether theorem. The "symmetry" is time and the Lagrangian mathematically describes this principle of least action. Which is very useful because you arrive to a conservation law. Nevertheless, thermodynamics tells that time is not a symmetry! the time in the future will have more entropy than the one in the pass. How can we put a non-symmetrical time in the Noether theorem? A entropic Lagrangian? I think there is a very big problem with time!
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NOTE: In consequence of some answers of users due to whom part of the issues become clarified, I do from time to time MODIFICATIONS in this question stressing the remaining questions.
Shan Gao, the author of the book
proposed a new interpretation for the QM: a substructurea of QM consisting in a moving particle. But instead of moving continuously, as in Bohm's mechanics, or as in the trajectories of all forms considered by Feynman in his path-integral theory, Gao's particle performs a random, discontinuous motion (RDM) - see section 6.3.2 and 6.3.3 in his book. In short, gao's particle jumps all the time from a position to another
"consider an electron in a superposition of two energy eigenstates in two boxes. In this case, even if the electron can move with infinite velocity, it cannot continuously move from one box to another due to the restriction of box walls. Therefore, any sort of continuous motion cannot generate the required charge distribution. . . .
I conclude that the ergodic motion of a particle cannot be continuous. . . .
. . .
a particle undergoing discontinuous motion can . . . “jump” from one region to another spatially separated region, whether there is an infinite potential wall between them or not.
. . . .
Furthermore, when the probability density that the particle appears in each position is equal to the modulus squared of its wave function there at every instant, the discontinuous motion will be ergodic and can generate the right charge distribution"
An important implication of the RDM interpretation is, as the author says, that the charge distribution of a single electron (for instance, in an atom) does not display self-interaction
"Visually speaking, the ergodic motion of a particle will form a particle “cloud” extending throughout space (during an infinitesimal time interval around a given instant), . . . . . . This picture . . . may explain . . . the non-existence of electrostatic self-interaction for the distribution.
Part of the questions regarding this picture were already clarified by the posts of some users. The questions remained non-clarified are:
1) Is Gao's picture of a particle jumping from position to position, and visiting in this way all the volume occupied by the wave-function, fit for obtaining the Feynman path integral?
Feynman considered two points in tim and space (t1, r1) and (t2, r2). He also considered all the possible paths between these two points - the majority of the paths having crazy forms, though being continuous. The particle starting at (t1, r1) and traveling to (t2, r2), was supposed by Feynman to be totally non-classical - it was supposed to follow SIMULTANEOUSLY all the paths, not one path after another. This is was permitted him to do summation over the phases of the paths, and obtain the path integral.
The movement of Gao's particle is not only discontinuous and endowed with no phase, but it os also SERIAL, one point visited after another. What you think, if one would endow these discontinuous trajectories with phases, could we obtain Feynman's path integral despite the seriality of his particle's movement?
3) Gao author also says
"discontinuous motion has no problem of infinite velocity. The reason is that no classical velocity and acceleration can be defined for discontinuous motion, and energy and momentum will require new definitions and understandings as in quantum mechanics"
This statement seems to me in conflict with the QM, because the uncertainty principle says that if at a given time a particle has a definite position, the linear momentum (therefore also the velocity) would immediately become undetermined. QM doesn't say that the linear momentum does not exist.
Can somebody offer answer(s) to my questions/doubts?
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Dear Sofia,
If you want to consider the self-energy problem for the electric charge presented in the Relativistic Quantum Mechanics for the quantized electromagnetic and Dirac fields, you are coming back to the beginning of the thirties of the past century. That was a big problem in Classical Electrodynamics worked by Lorentz and Poincarè among others. The concentration of the electric charge in one point leads us to infinite mass but its spatial dispersion can make weaker the interaction but without avoiding its repulsion.
Fortunately, mainly due to Schwinger, Feynman and Tomonaga (nobel prizes) we can explain how this energy can be finite and converge within a physical context of QED, i.e. within a polarization of the vacuum and the renormalization group. This makes us to calculate properly the cross section of a charged particle in agreement with experiment and to use a pointlike picture for an electric charge, but this is just a model. Nobody can tell how the electric charge distributes in one electron, for example. But the idea that the charge of a particles is spacially distributed doesn't like me because its value is always constant and following the Coulomb law with a great accuracy, in the static case. Thus I still follow with the idea that we have particle-wave picture as a complementary physical point of view.
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FVM methods are usually used to solve the hyperbolic conservation laws. Why we can not use finite element methods for this? Is there any other reason than the inherent conservation property associated with FVM?
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Some of the main features of the FVM are similar to those of the FEM (i.e. Oden, 1991). Nevertheless, one of the most interesting features of FVM is that the numerical fluxes are locally conserved based on a “ balance” approach from one discretisation cell to its neighbour. This feature is necessary condition in fluid dynamics and helps us to keep for example the total mass or potential vorticity conserved for i.e. in adiabatic case of rotating shallow water model.
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How do we nicely represent specific entropy conservation law in a mathematical form in diversified astrofluids?
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Entropy: A concept that is not a physical quantity
All this time, people thought that dQ was not a complete differential, but dQ/T was considered as a complete differential.
However, this is wrong.
The facts are just the opposite: dQ is actually a complete differential, but dQ/T is meaningless.
in ΔQ/T, the relationship of Q and T is the ratio of ΔQ and T or the product of 1/T and ΔQ, so, in ΔQ/T, Q and T can be any relationship.
But in dQ/T, the relationship of Q and T is not the ratio of dQ and T or the product of 1/T and dQ, but the relationship to Find the Original Function of 1/T in dQ/T=1/TdQ.
For we know Q is not a single-valued function of T, (in fact, Q=f(P, V, T) ), so, ΔQ/T can NOT turn into dQ/T, or say, dQ/T is meaningless.
The problem is not whether dQ is meaningful or not here, it is 1/TdQ is meaningless !
Q = f(T, V, P) is a process quantity which varies with path, it has innumerable forms between the same original and terminal states, and has a unique form for fixed reversible process path. When the given path is fixed, Q = f(T, V, P) is the system state variable.
So, dQ=df(T, V, P) is a perfect differential, it is meaningful;
but the integral variable of 1/TdQ is self-contradictory (T and T, V, P), so, 1/TdQ=1/Tdf(T, V, P) is meaningless, that is ∫T 1/TdQ = ∫T 1/Tdf(T, V, P) is not a meaningful integral, or say, it is not a integral at all.
That is, ΔQ/T can NOT turn into dQ/T,
there is not the result∮1/TdQ=0 at all.
The so-called "entropy" does NOT exist at all.
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Astrofluids are characterized with the help of various thermodynamic properties and associated conservation laws. In this context, can anyone give a realistic correlation between the specific entropy conservation and logatropic pressure of such fluids?
Relevant References and materials dealing with new equations of state are as well welcome.
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ΔG = Δ U -TΔS +P Δ V According to the postulated entropy conservation (That means one has an adiabatic process, D S=0 in this question) above equation takes the following form:
ΔG = ΔU + P ΔV According to the Thermodynamics for closed system ΔG is negative for irreversible changes and is equal to zero for reversible changes, and it can never be positive since that iöplies unnatural process which never takes in nature!! The mathematical inequality may be put into the following form.
ΔU EQ L ( - P Δ V) , In the case of reversible change one has:
ΔU = -P ΔV Decrease in the volume increases the internal energy or visa versa. In the case irreversible process the increase is less than the work done on the system during contraction, and that difference appears as a dissipation of energy.
In my work on the irreversible processes under the isobaric isothermal conditions, one has: - Δ G/T = S Internal S is Positive definite quantity called internal entropy production.
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Request for information
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Andrew, I'd be interested in what you find. Have had a side interest in Dhub for a long time and the declines in Oman seem to be serious.
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In recent times we have seen so much work being done related to fractional partial differential equations, especially in the field of Lie symmetry analysis and conservation laws. In case of partial differential equations where the conservation laws can be determined using various methods like; Noether's theorem and direct method of Bluman and Anco. For non-trivial conservation laws, the divergence expression of fluxes must annihilate on the solution space of PDE under consideration.
My query is, whether such annihilation of fluxes also holds for conservation laws of a fractional partial differential equation?
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Dear Professor Singh,
Your question is quite interesting. Actually, the key point is: What is a conservation for a fractional differential equation (FDE)?
As far as I understand (I´m not an specialist in the field of FDE), some definitions of the derivative operator does not necessarily satisfy the vanishing of the "fractional" vector fields. Of course, this is a problem with our classical definition of conservation laws. Moreover, as far as I know (and hope, I am wrong), we do not have physical phenomena modelled by FDE yet, although many groups of researchers try to find one. This certainly would be helpful to understand better the situation, even more if the phenomena had something conserved.
I have seen some tentative of Noether type theory for constructing conservation laws for FDE, but I do not know how successful they have been.
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Hello André,
Thank you, but discussion on non-newtonian physics is off-topic here, and there's no need to reaffirm my viewpoint expressed above, the sentences seem clear. Maybe this fits in other threads at RG.
Cheers, Ed Gerck
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For example, in the context of this project and what students should learn in today's crowded curriculum, consider this quote from Benjamin Crowell [1]:
In many subfields of physics these days, it is possible to read an entire issue of a journal without ever encountering an equation involving force or a reference to Newton's laws of motion. In the last hundred and fifty years, an entirely different framework has been developed for physics, based on conservation laws.
The new approach is not just preferred because it is in fashion. It applies inside an atom or near a black hole, where Newton's laws do not. Even in everyday situations the new approach can be superior. We have already seen how perpetual motion machines could be designed that were too complex to be easily debunked by Newton's laws. The beauty of conservation laws is that they tell us something must remain the same, regardless of the complexity of the process.
[1] Benjamin Crowell, Light and Matter, chapter 14, retrieved from
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Hello Christian,
Yes, and thank you for bringing in the children.
Once, giving a talk to my son's fourth grade class, 9 years old, I asked the students what numbers could be divided by two, and gave the list 1,2,3,4,5,6,7,8,9,10. All the students said 2,4,6,8,10, very proudly. I remarked that any number can be divided by two. For example, I explained, if you give a little 3 year old girl a cookie, who never went to school, and ask to share with her sister, she will divide it in half, and give half to the sister. What is lost in school, I asked. The wrong intuition is given to kids, under the guise of simplication. Then, we started to talk, and their attention amazed me and their teacher.
I just presented a comment in RG, that fits the first part of your comment, on physics. To avoid duplication, please refer to it (third answer) in the link: https://www.researchgate.net/post/In_a_physics_context_what_do_students_find_difficult_in_using_Lagrangian_and_Hamiltonian_methods
Cheers, Ed Gerck
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  I try to study the existence of a time periodic solution for the compressible with a time periodic outer force (without relaxation term) . I have recently obtained .
However, this result is restrictive. Do you know a result about this problem under more weaker condition?
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Thank you for sending me files, Prof. Bo-Chih Huang. Thank you for respense, Prof. Hayakawa.
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Hello,
If a Lagrangian is known for a given system, we can deduce its equation of motion using the Lagrange equation.
Are there any other uses of a Lagrangian?
One use I know is to find a conservation law for a mechanical system. If its Lagrangian does not include time explicitly, we can obtain a conserved quantity by Jacobi integral.
I am wondering what other applications are possible with a Lagrangian (especially for engineering fields.)
Thank you.
David
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@ David, Some examples in engineering field where Lagrangian concept is used are:
Civil Engineering: Brachistochrone problem, Given two points 1 and 2, with 1 higher above the ground, in what shape should we build a frictionless roller coaster track so that a car released from point 1 will reach point 2 in the shortest possible time?  The concept is used in the designing of ski-jump platforms.
Another example is the design of a bridge of "catenary" in shape.
Automobile and Rocket Engineering: There are various moving parts in cars/bikes/rockets. Lagrangian mechanics is used to achieve optimal control status of these dissipative systems.
Hope that helps.
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am trying to find the  conservation laws of ZK-BBM equation with multiplier method on maple where Un is appear in the PDE but maple is not working with n will any body tell me how i do it. maple is showing the results for particular value of n but in general fails.
any suggestion please??
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Many thanks Prof. Bo Ren
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Dirac said that a 'linear' polarized photon is a superposition of left and right rotating photons. Here is a puzzling aspect of this superposition.
There are dichroic materials which can absorb only left photons. What is their effect on this superposition? They would absorb the left state and let the right. It turns out that there are two photons in a 'linear' photon! The mechanical momentum of the dichroic material must be measurable in principle  (like Beth experiment). It would be expected that there is some energy hv absorbed too but it must be in the right photon also. Conservation of energy seems broken? If there is no momentum and no energy absorbed in the dichroic the conservation laws are also severely harmed. At least something happens to that photon (linear to right which is easy to show) but nothing happens to the causer of this event (namely to the dichroic). I see that there must be wavefunction collapse for the photon and in fact the question boils out to:
Is something physically happening to the machinery causing the collapse?
This question is connected to the following question:
Is there any way to split a linear polarised photon into left and right polarised photons? - ResearchGate. Available from: https://www.researchgate.net/post/Is_there_any_way_to_split_a_linear_polarised_photon_into_left_and_right_polarised_photons [accessed Feb 12, 2016].
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Hi Lothar,
Sory for your illness. Hope you fully recovered.
It took me some time to prepare my answers.
1. About the Beth experiment
I haven’t read the original paper but a description from “Beth’s experiment using optical tweezers” D. N. Moothoo, J. Arlt, R. S. Conroy, F. Akerboom, A. Voit, and K. Dholakiaa)
….. ‘Beth followed up Poynting’s suggestion in his experiment where he measured a torque on a suspended birefringent half-wave plate as circularly polarized light passed through it, thus reversing its sense of rotation—that is, changing its handedness from left-handed to right-handed or vice versa.
The torque resulted from the conservation of angular momentum between the light and the plate as each photon passing through the plate transferred 2h of angular momentum to the plate ~see Fig. 1!.’
2. About the zero mass of photon and the lack of spin = 0 (as explained by high energy physicists)
If the spin of a massive particle is 1 than it can have projections -1, 0, and 1. As the photon is massless there is not reference frame where it is at rest. The spin 0 for the photon means a photon that has velocity zero, which of course is impossible.
If you want to show that s=0 for linear photon this is what you have to disprove.
3. About the velocity of the electron
I see that v(r) is proportional to m. You prove this for Schoedinger equation all right. Nevertheless I am not convinced that this means that the transition l=2 / l=1 leads to photons linear and with spin 0.
Reason: What does m mean? It is the projection of L on a specified axis z. So if a state has m=0 for an axis z one can choose another axis z’ and there the projection of L would be not 0, but 1 or -1. (respectively 2, -2 for l=2). Then the velocity is not 0.  Maybe this can be interpreted as the velocity is not defined.
I can not say it definitely but this is a point which is not clear to me.
Another reason is that the correct equation for the atom is that of Dirac. I don’t know if you can show this conclusion [v(r) ~m ] for Dirac?
I am very curious about this observation you made about v=0 for m=0. Have you published it anywhere and if yes what reactions did you get? Becase v=0 for the electron is more than strange.
Ilian
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There are many indications that this is the case today, with the added advantage that Newton's laws can then be derived rather than proposed. For example, consider this quote from Benjamin Crowell  [1]:
In many subfields of physics these days, it is possible to read an entire issue of a journal without ever encountering an equation involving force or a reference to Newton's laws of motion. In the last hundred and fifty years, an entirely different framework has been developed for physics, based on conservation laws.
The new approach is not just preferred because it is in fashion. It applies inside an atom or near a black hole, where Newton's laws do not. Even in everyday situations the new approach can be superior. We have already seen how perpetual motion machines could be designed that were too complex to be easily debunked by Newton's laws. The beauty of conservation laws is that they tell us something must remain the same, regardless of the complexity of the process.
[1] Benjamin Crowell, Light and Matter, chapter 14, retrieved from
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The really meaningfull term in physics, and more broadly in science, is generality.  But to appreciate generality, one must first know all the cases where it applies, otherwise it can not be recognized as such.
Under the light of generality, opinions may show their limits. The Lagrangian formalism isn't the more general one. It doesn't apply when non conservative forces appear, then new definition of energy must be given, along with sattelite concepts like free energy or enthalpy, so that energy conservation also rules in thermodynamics.  As Noether theorem only applies in the Lagrangian and Hamiltonian formalims, it is useless in this case. Moreover, if a symmetry implies a conservation law, the converse is not true, there are topological invariants for instance.  Of course there is statistical mechanics, but that doesn't include non holonom systems, which need Newtonian mechanics, and which I think will play an important role in physics.
In all that, momentum conservation is the most general, that's why it should not be taught first.  I don't say it should not be taught at all, to the contrary, that is the target of the whole course in physics.  Science developed in the way it did for the same reason, it took the most easy way, and its purpose is generality which is gradually gained.
It is as though one would say that the top of the pyramid is the most important part, since it can be seen from the farthest, then it must by laid first.
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I have not been able to find a concrete list of exactly what species are illegal to ship across state lines. Whenever I am purchasing arthropods online for research purposes, I see websites that say "We cannot ship to Florida or Hawaii," but I haven't been able to find anything explaining this in writing other than a few people telling me that they think it's illegal to ship some insects to those states but they don't know which ones.
Some websites I see say that you need an import permit for EVERY arthropod species you plan to bring across state lines. And that it is always illegal to ship any non-U.S. native insect or millipede across state lines! I find this hard to believe... for example, I know that many people purchase Dubia Roaches online to feed their reptiles, and get them shipped across the country. Dubia Roaches are native to South America, however there are thousands of people who sell them in the U.S. including legitimate businesses like DubiaRoaches.com.
I am worried that I will think I've got all the laws sorted out based on what people say, then I will go ship some of my extra research specimens to someone in another state and the USDA will pound on my door! Any help would be appreciated, thanks!
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In the U.S., Interstate movement of “live plant pests, biological control agents, bees, parasitic plants, federal noxious weeds, or soil” is regulated by USDA-APHIS-PPQ. The permit for shipment is obtained by the recipient. If you are receiving insects, it is better (and more professional) to take a broad view of the above category. The sender should have copies of the permit, and include them inside the shipment of insects. The APHIS PPQ FAQ for this purpose can be found here:
APHIS PPQ general works with the recipient’s plant protection authority; e.g., for California, California Department of Food and Agriculture (CDFA). Often the permit process can be expedited if California recognizes that a species you wish to receive is already resident; see:
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Hello everyone,
I am reading CFD by John D. Anderson. I understood the derivation of different forms of Navier-Stokes equations. But it is still unclear for me what is the fundamental difference between Integral and differential forms of the Navier-Stokes equations. It is also not clear for me where are these forms used ?
I always see all the explanations based on the Differential forms so I am wondering if the integral forms are used ?
Another thing : Please correct me if I am wrong ::
The conservative and non-conservative forms are called like that because, the conservative forms are derived from a conservation law and the non-conservative forms are not.
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Hello Aditya!
Both equations tell the same tale: the conservation of momentum. One is formulated for  an infinitesimal fluid particle (the differential form) whilst the other is applied to a region in space, the control volume. These two are linked by the Gauss theorem, and can be derived via almost ten different ways. Both originate from the same first principles (the Newton's 2nd law of motion). Mathematically, they are equivalent in the infinitesimal limit.
For numerical solutions, the differential form is used together with difference approximations (FDM, finite difference method). Integral form is used with the finite volume method, FVM. These are equivalent in uniform grids. The differential form does not have a solution in the classical sense in presence of discontinuities (eg. compressible flows with shocks), hence, one uses the weak form of the integral equations. A physically unique solution is sought using an entropy condition.
The conservative property has a numerical aspect, concerning the overall conservation. This is usually important in an approximate solution; FVM are better in this respect. For example, a conservative momentum flux is \nabla . \rho u u, while u . \nabla \rho u is not. In differential form these are again equivalent but one can never can shrink the grid spacing infinitely to ensure the solution of the differential equations is that of the integral equations applied to an infinitesimally small control volume.
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In spite of appeals to international and national NGOs as well as to national and regional agencies it has (so far) been impossible to obtain information on areas of highest conservation priority in the Brazil's Mata Atlântica. The goal is to purchase land for permanent conservation as a Reserva Particular do Patrimônio Natural. Any suggestions from ResearchGate will be much appreciated.
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Alexandre,
After a year during which scores of appeals for Mata Atlântica RPPN information were sent fruitlessly to over a dozen NGOs and government agencies, a single request on ResearchGate has inundated me with valuable data. I haven't had time to retrieve, still less review, the MMA book you recommend but I am sure it will prove valuable.
The second RBMA work has already been useful. Sincere thanks. And it is personally interesting because a specimen of one of the very threatened palms mentioned has grown in my garden for several years.
You commented:
> ...the several other [areas] are still waiting for a “political suitable environment” (that hopefully will not take 20 years!).
Of course. Perhaps, remembering Margaret Mead's“Never doubt that a small group of thoughtful, committed citizens can change the world; indeed, it's the only thing that ever has”, one small NGO can help create that environment.
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By definition, a reversible process is one that can be undone completely, leaving no trace of it having occurred. Upon reversal "it should be impossible to devise any experiment that could determine whether the process took place" (paraphrasing Planck). This means that every single bit of information that was flipped by such a process going forward, should be flipped back when the process finishes going in reverse. This really means all causal volume traces must be erased including all memories recorded in labbooks, hard drives or brains. Postulating the existence of such a process is therefore an unfalsifiable assumption (since if you succeeded in performing such a process there would be no evidence to show for it and you wouldn't even remember doing it!). This means asserting the existence of truly "reversible" processes is no more than an act of faith. Yet significant portions of physics depend on this belief and we try hard to keep the "micro" laws time-reversible. Since reversible processes are defined as those that can never make their presence known by affecting anything, it means that experimental evidence of CPT violation is inevitable and the microscopic arrow of time is down there, it's just hard to see because of the limitations of current experiments. It follows that the notions of determinism, unitarity of quantum mechanics, symmetries etc. should be understood as approximations the same way as Plato's perfect circle is never realized in any physical system. Keeping these self-contradictory notions at the heart of the mathematical underpinnings of physics as "useful approximations" is confusing physics with engineering. Worse still, our instinct to treat absolute conservation laws as sacrosanct is seriously harmful to furthering our understanding of how it all really works.
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@Andreas. I think your interpretation of Planck is possibly overly strict. I was always taught that if you take a video of a process, and run the video backwards, and find no essential difference, then the process is reversible. (The video itself has recorded the process, but that doesn't count. You've been too strict IMO).
This picture applies equally to thermodynamic reversibility. When you have a process in thermal equilibrium, the *net* motions you see in the video will be indistinguishable whether you run the video backwards or forwards. However, if the resolution of the video is fine enough and you zoom in, you'll see microscopic fluctuational differences between the forward and reverse videos. But that is not the point. That is too fine-grained for thermodynamics. Concepts such as equilibrium are obtained by averages over a timescale bigger than the fluctuations, and don't apply at a fluctuational instant. So we are able to call this case reversible at a long time scale, but not over a nanosecond.
It is for this reason I prefer the slightly more relaxed "video based" definition of reversibility rather than your very strict one.
Under the relaxed definition, many things are approximately reversible in the classical world, depending on scales. Nothing is ever perfectly reversible in the classical world. There is always leakage into the environment, whatever you do.
In the quantum world you ideally have reversibility. But there is never perfect isolation from the environment. So reversibility is ephemeral.