Thermophones Produce Sound Without Vibration

In 1914, Lord Rayleigh communicated the description of the thermophone by de Lange to the Royal Society. But as early as 1880, Preece produced sound by passing current through micron sized platinum wires affixed to a diaphragm. Around 1800, the Russian engineer Gwozda produced sound by heating a straight wire without a diaphragm. Historically, the theory of thermophones is based on the production of sound from a thin platinum film published by Arnold and Crandall in 1917.
    Recently, Xiao et al. showed sound was produced by passing an alternating current through thin carbon nanotube (CNT) films. The high sound level at low electrical power for the CNT films were thought more efficient than platinum that required more power for the same sound level. However, the experimental frequency response did not agree with the long standing thermophone theory of Arnold and Crandall. Modifications were made to the theory including the conductive heat loss from the film to the air based on classical heat transfer methodology. See “Thermophones,” at link “Nano Letters Paper”, of , 2009. Xiao et al. claim agreement of the modified theory and experimental data. However, the claimed agreement could not be confirmed by this author because of the experimental fitting necessary to determine the conductive heat loss.

Problems with Classical Heat Transfer Theory
Classical heat transfer theory predicts that sound levels in thermophones are produced by changes in thin film temperature caused by Joule heat produced from passing electrical current though the films. However, this cannot be correct. Classically, temperatures should increase in CNT thin films in proportion to the electrical power, but the CNT films produced high sound levels at lower power than in platinum films at high power levels.
   What this means is that temperature changes in thin films have nothing to do with the sound produced in thermophones. Alternatively, classical heat transfer theory that predicts sound is produced by temperature changes in thin films is not applicable to thermophones.      

Heat Transfer under Quantum Mechanics Restrictions
Quantum mechanics (QM) methodology differs from classical heat transfer in that the specific heat of the atom is required to vanish under electromagnetic (EM) confinement. Ibid, “Thermophones,” at link “Paper”. In heat transfer restricted by QM, Joule heat absorbed in the thin film cannot be conserved by an increase in temperature. Classical theory differs in that specific heat of materials in macroscopic structures is assumed to remain the same at the nanoscale.
   Regardless, EM energy is still required to be conserved at nanoscale. Lacking specific heat, thin films conserve Joule heat by the theory of QED induced EM radiation. QED stands for quantum electrodynamics. By this theory, the low frequency Joule heat is conserved by frequency up-conversion to the EM confinement frequency of the film. Like creating photons of wavelength L by supplying EM energy to a QM box having sides separated by L/2, the Joule heat in thin films creates photons having wavelength L = 2nd, where d is the thickness and n is the refractive index of the film. There is no increase in temperature of the thin film.
   The QED photons are only confined briefly because the EM confinement is quasi-bound, and therefore the thin film promptly leaks EM radiation at the confinement wavelength. Typical CNT thin films in thermophones have thickness d > 0.125 microns, and therefore the EM confinement produce radiation in the ultraviolet (UV) and visible (VIS). Unlike thermal radiation in classical heat transfer theory that requires high temperatures, the QED induced emission is non-thermal and occurs at ambient film temperatures.  

Sound from Thermophones by QM
Sound from thermophones requires pressure changes in the surrounding air. The QED induced emission in the UV-VIS is therefore required to be absorbed by air to increase its temperature and produce the pressure changes necessary for sound propagation. But nitrogen in air is transparent in the UV-VIS and cannot produce sound. Only oxygen has an absorption cross-section close to that necessary to produce sound. The Joule heating necessary to produce sound by oxygen absorption is found to be a very small fraction – around 10^-6 of the 1-4.5 watts supplied.
   Almost all of the supplied Joule heat is lost to the solid walls of the thermophone enclosure. To improve thermophone efficiency, the gas volume between the thermophone and microphone should be sealed and filled with a UV-VIS absorptive gas.

   1. By quatum mechanics, sound is produced by QED emission without vibration. Classical heat transfer is unable to explain sound without vibration.

   2. Classical heat transfer that includes finite specific heat in thin films is not applicable to thermophones. The Joule heat cannot be conserved by temperature changes of the thin film.

   3. Heat transfer by QED induced radiation as based on zero specific heat as required by QM should be used for the analysis of thermophone performance. The emission of UV-VIS radiation that conserves the Joule heat is required to be absorbed by the air surroundings to produce sound.  

 4. But the absorption of UV-VIS in air is very low.  Indeed, almost all of the Joule heat does not produce sound because of absorption by the walls of the enclosure. To improve sound levels, the space between the thermophone and microphone should be sealed and filled with a UV-VIS absorptive gas.

Nanocars are powered by electrostatic forces from QED induced charges

Nanocars comprising fullerene spherical wheels on hydrocarbon axles are shown to move on substrates by electrostatic forces from charges produced by quantum electrodynamics (QED)

Nanocars evolved from research that began over a decade ago. At the IBM Zurich Research Laboratory, synthetic molecules (S-molecules) on a metal substrate were moved in a controlled and repeatable manner by pushing them with the tip of a scanning tunneling microscope (STM). See … .

The S-molecules included an organic molecule called porphyrin comprising a ring of atoms about 1.5 nanometers in diameter with a metal atom at its center. Groups of hydrocarbons were added to the porphyrin to provide four leg supports. The function of the legs was thought to allow the S-molecule to grip the surface to stabilize random thermal motion. Friction between the legs and the substrate could not have been significant because upon nudging with the STM tip the S-molecules appeared as though they were on rollers.

Quantum Mechanics Explanation
The S-molecule motion may be explained by quantum mechanics (QM). The Einstein-Hopf relationship for the QM harmonic oscillator shows the thermal kT energy of an atom at ambient temperature resides in the far infrared (FIR) beyond 50 microns. Here, k is Boltzmann’s constant and T is absolute temperature. But the S-molecule by its size excludes all thermal radiation beyond a few nanometers, and therefore lacks the heat capacity to conserve the FIR heat absorbed from the contact of the legs with the substrate by an increase in temperature. Upon contact of the legs with the substrate, the S-molecule becomes a part of a macroscopic body that by QM is allowed to have kT energy. But in moving, the S-molecule breaks contact to be momentarily isolated from the substrate, and therefore has excess kT energy above the vanishing small amount allowed by QM.

Lacking heat capacity, the S-molecule cannot conserve the excess kT energy by an increase in temperature. Conservation therefore may only proceed by the QED induced frequency up-conversion of the excess kT energy in the FIR to the electromagnetic (EM) confinement frequency of the S-molecule, which at ultraviolet (UV) levels and beyond has the Planck energy to charge the S-molecule by the photoelectric effect.

The QED induced charge only produces momentary electrostatic interactions. Nevertheless, the S-molecule is held to the substrate by momentary electrostatic attraction instead of by gripping as initially thought. Lateral motion depends on the momentary electrostatic interaction with its neighbors. In a random arrangement of S-molecules, the electrostatic interactions are not symmetric and on that basis alone may initiate motion. Moreover, lateral motion over the substrate occurs by intermittent stick-slip, but small friction at contacts makes it appear as though the S-molecule is on rollers. Regardless, contact neutralizes the charge on the S-molecule and allows the kT energy to be reacquired from the substrate to allow subsequent breaking of contact to produce QED charge. During stick-slip motion, the intermittent QED induced charge occurs very rapidly and may be difficult to detect.

Today, nanocars moving on substrates are more complex than the S-molecules, but the QED charging is the same. Currently, many research groups are engaged in nanocar research typified by Rice University. See ….

In QED charging, nanocars like S-molecules are powered by converting EM energy into mechanical motion. The EM energy may take various forms of heating including light, thermal, Joule, and electron beams. Indeed, nanocars have been shown to move by simply heating the substrate, the form of heat being the same thermal kT energy driving the earlier S-molecules. In effect, nanocars act as FIR to higher frequency up-conversion devices that charge the nanocars by producing momentary electrostatic repulsive forces that produce the observed nanocar motions. Similar arguments allow QED charges to explain the motions of molecular motors under Joule and electron beam heating. See at “Nanocars by Quantum Mechanics”, 2010.

Molecular Dynamics
Unfortunately, the QED charging by which thermal kT energy is converted into powering the nanocar is not included in a conventional MD solution that implicitly assumes atoms have kT energy at the nanoscale. Valid MD simulations in heat transfer need to specify vanishing kT energy in the MD computational algorithms, and if so included would give isothermal temperature solutions. The invalidity of MD in heat transfer at the nanoscale is widespread, e.g., in tribology, see ; whereas, in nanocars, see

MD is not needed for heat transfer at the nanoscale because temperature solutions are, a priori known to be isothermal. However, QED induced charging in nanostructures can and should be included in MD simulations of dynamic response, at least within the restrictions of Newton’s equations.


1. Nanostructures including S-molecules, nanocars, CNT motors and the like act as frequency up-conversion devices that are charged from QED radiation by the photoelectric effect, thereby allowing pair-wise interactions by momentary electrostatic repulsion.

2. MD simulations of heat transfer in nanocars are precluded by QM. At ambient temperature, the thermal heat capacity resides in the FIR beyond 50 microns, and therefore nanocars by their size exclude the heat capacity necessary for heat transfer. MD simulations of heat transfer in nanostructures are simply meaningless.

3. Unlike heat transfer, MD simulations are valid if directed to deriving the dynamic response of nanostructures on substrates under momentary QED induced charges.

Quantum Mechanics Questions the Molecular Dynamics of Submicron Structures

In the 1950s, Metropolis and Teller pioneered molecular dynamics (MD) as a method to derive the thermodynamic and transport properties of bulk molecular liquids. Submicron ensembles comprising a few hundred atoms with periodic boundary conditions were used to derive the bulk liquid properties. Even though the ensembles were submicron, the periodic boundary conditions allowed the heat capacity of the atom at wavelengths longer than the dimensions of the ensemble to be included in the MD simulations.

Today, MD simulations have been extended almost entirely to discrete submicron structures. See WTC IV The implicit assumption in the later MD simulations was there is no difference between the thermal heat capacity of the atoms in the discrete submicron structures and those ensembles in MD simulations with periodic boundary conditions.

However, quantum mechanics (QM) as embodied in the Einstein-Hopf relation shows the thermal heat capacity of the atom as given by the Planck energy of the harmonic oscillator depends on dispersion with wavelength. At ambient temperature, most of the thermal heat capacity of the atom is available at wavelengths > 100 microns where the thermal kT energy is about 25.8 meV. But the thermal emission from atoms in submicron structures is confined to wavelengths < 1 micron, and therefore excludes almost all of the heat capacity of the atom. Alternatively, atoms in discrete submicron structures in MD simulations lack the heat capacity necessary to conserve absorbed EM energy by an increase in temperature.

MD simulations of discrete submicron ensembles may proceed as usual provided the QM restriction on the heat capacity of the atoms is properly simulated. One such method is the theory of QED induced radiations. See QED radiations Lacking the heat capacity to conserve absorbed EM energy by an increase in temperature, the absorbed EM energy is frequency up or down-converted by QED to the EM confinement frequency of the submicron structure. Subsequently, the absorbed EM energy is conserved by the emission of non-thermal EM radiation.