The effective mass of electrons (mₑ*):

In the 80s, in our electronics classes in semiconductor or solid state physics, such as semiconductor diodes, LEDs, transistors, integrated circuits, BJTs, thyristors, triacs, fets, mosfets and many more, we learned the effective mass of electrons, a very interesting topic, which I'm sharing now.

Electron effective mass (mₑ*) is a concept in solid-state and semiconductor physics that describes the behavior of electrons in a crystal lattice or semiconductor material. In these materials, electrons experience periodic potentials, causing them to behave differently based on their momentum and the crystal's band structure. Effective mass is the modified mass of electrons, which can vary in different crystal directions. It is determined experimentally or theoretically from the element's electronic band structure. In some cases, the effective mass of electrons in a semiconductor can be negative, causing unusual phenomena like negative differential resistance.

It is important to note that the electron rest mass (mₑ) is a fundamental constant and is always the same for electrons, regardless of the material in which they reside. On the other hand, electron effective mass (mₑ*) is a material-dependent property that describes how electrons behave in certain materials under certain conditions.

Question: Lorentz transformation involves mass change but mass cannot be transformed into another form?

Answered by Others: The Lorentz transformation is a mathematical tool that helps understand how physical quantities change under relativistic conditions. It does not involve the direct conversion of mass into another form, such as energy or frequency. The Lorentz transformation deals with the relativistic effects of high velocities.

In the context of the Lorentz transformation, the mass of an object does not change. The concept of "relativistic mass" was introduced in the early days of special relativity to describe how an object's mass appears to change with its velocity. However, this concept has fallen out of favor in modern physics, and the more accepted view is that an object's mass is an invariant quantity, meaning it remains the same regardless of its velocity or the reference frame from which it is observed.

The Lorentz transformation does not involve any change in an object's rest mass. It is a mathematical tool used to understand how physical quantities vary between different inertial reference frames and is consistent with the principles of special relativity. Mass (m) remains an invariant quantity in all inertial reference frames, meaning its value remains the same for all observers, regardless of their relative velocities.

Massless discrete energy (hf) is stored in matter mass (m) without considering wave speed:

Author: Soumendra Nath Thakur ORCID iD: 0000-0003-1871-7803 

Dated 30-July-2023, Country: India.

Summary: Mass and energy are interconnected, but not always. Energy exists without being converted into mass, such as photons. Mass is converted into energy through nuclear reactions, fission, fusion, or radioactive decay. Energy is stored in mass without considering wave speed. Energy conversion units include Joules and electron volts. Small amounts of mass can be converted into energy through fission, fusion, or spontaneous radioactive decay.

Description: Energy exists in massless subatomic particles like photons, but not always vice versa. Electrons absorb photons without mass change. Mass converts into energy through nuclear reactions or radioactive decay. Discrete energy is stored in the mass without nuclear reactions, without considering wave speed. 1 kg m^2/s^2 energy is the derived unit of 1 joule in SI units for mass-energy conversion. The electron volt (eV) is a unit of energy. 1 eV = 1.6 * 10^-19 J. Incredible amounts of energy are converted from small amounts of mass through fission, fusion, and spontaneous radioactive decay. The mass of matter (m) contains discrete energy, similar to the atomic nucleus, electron, and electron energy. 

Conclusion: Therefore, when mass represented by (m), it is equal to (m + Em) or (m + hf) or (m + Ep), representing the cold mass of matter, the discrete energy of the mass, the discrete energy of the photon at its frequency, or the discrete energy corresponding to Planck's constant, respectively.

Lorentz transformation, but mass cannot be transformed into another form:

It's nice to say that where there's mass, there's energy, but not always it's actually the opposite.

Because some forms of energy exist without being converted into mass. such as massless energetic subatomic particles, such as photons.

A photon absorbed by an electron is not converted into mass but remains there as electron energy, without changing the electron's mass.

Mass is converted into energy by nuclear reactions of atoms, especially through fission and fusion, or spontaneous radioactive decay in unstable atoms.

Otherwise, mass is not converted to pure energy without nuclear reactions but instead energy is stored in the mass without consideration of the wave speed.

In mass-energy conversion, 1 kg m^2/sec^2 mass of energy is called 1 Joule. Thus, the Joule is a derived unit of energy in SI units.

The electron volt (eV) is a unit of energy.

1 eV = 1.6 * 10^-19 J.

In particular, small amounts of mass are turned into energy from the breaking up through fission, or by combination through fusion of the nuclei of atoms. 

Even spontaneous radioactive decay converts some mass into incredible amounts of energy.

In conclusion, Lorentz's transformation of mass into another form is physically false.

Experiment made with piezoelectric film sensors:

When a mechanical force is applied to the piezoelectric film sensor, the seismic mass loads the piezoelectric element according to Newton's second law of motion F=ma. The force applied to the piezoelectric material is observed in the change in electrostatic force or voltage generated by the piezoelectric material.

#piezoelectric #PiezoelectricFilmSensor #PiezoelectricCrystalOscillator