Alexander L Dmitriev

Alexander L. Dmitriev
Residence	St. Petersburg, Russia
Nationality	Russian
Known for	Experiments reporting a negative temperature dependence of weight; frequency-dependent free fall of rotating bodies; experimental challenges to the equivalence principle
Scientific career
Fields	Physics, Experimental gravitation, Optics
Institutions	St. Petersburg National Research University of Information Technologies, Mechanics and Optics (ITMO University)

Alexander L. Dmitriev is a Russian experimental physicist based in St. Petersburg, associated with the St. Petersburg National Research University of Information Technologies, Mechanics and Optics (ITMO University). He is known for a long series of precision weighing and free-fall experiments in which he reports small but reproducible deviations in the weight of bodies that depend on their temperature and on the rotation of internal mechanical rotors. Dmitriev argues that these results indicate that the force of gravity is not strictly determined by mass alone, and that the equality of inertial and gravitational mass — the empirical basis of the equivalence principle — should be regarded as an open experimental question rather than a settled one.

Biography

Dmitriev works in St. Petersburg, Russia. His papers give his affiliation as the St. Petersburg National Research University of Information Technologies, Mechanics and Optics (ITMO University), 49 Kronverksky Prospect, St. Petersburg; some later publications also list the Baltic State Technical University "VOENMEH" in St. Petersburg. His background is in optics and optoelectronics, and alongside that work he has taught and published in gravitational physics and experimental physics.

Much of his gravitational work has been carried out with collaborators including E. M. Nikushchenko, V. S. Snegov and S. A. Bulgakova. His results have appeared in Russian journals such as Russian Physics Journal and Measurement Techniques, in AIP Conference Proceedings volumes associated with the Space, Propulsion and Energy Sciences meetings, in Applied Physics Research, and as preprints in the general physics section of arXiv.

Scientific contributions

Negative temperature dependence of weight

Dmitriev's best-known claim is that the weight of a body decreases slightly when the body is heated — a negative temperature dependence of the gravitational force. In a 2003 paper with E. M. Nikushchenko and V. S. Snegov (Measurement Techniques) he reported weighings of metal rods heated by ultrasound in which the measured weight fell as the temperature rose. In a later, deliberately simple version of the experiment (2012), a thermally insulated copper sample of about 28 grams was heated by a tungsten spiral inside a sealed vessel; Dmitriev reported a reduction of the apparent weight of about 0.7 mg, and discussed at length the possible sources of systematic error such as convection, buoyancy and thermal drift of the balance.

He has emphasised that this is the opposite of what is usually expected: on the standard relativistic account the extra internal energy of a hot body should make it very slightly heavier, by an amount far too small to weigh. The effect Dmitriev reports is many orders of magnitude larger than that, and of the opposite sign. He has argued that his measurements are consistent with the much earlier experiments of P. E. Shaw and N. Davy (1923), which also indicated a temperature dependence of gravitational attraction, and he has proposed a kinematic interpretation in which the accelerated microscopic motion of the particles of a heated body reduces the net gravitational force acting on it. He has also suggested that the same dependence should show up in astrophysical settings and in the routine practice of thermogravimetric analysis, where he holds that ignoring it limits measurement accuracy.

Rotating bodies and free-fall experiments

A second line of Dmitriev's work concerns bodies containing a spinning rotor. With Nikushchenko and Bulgakova he measured the free-fall acceleration of a sealed container holding a mechanical gyroscope whose axis was horizontal, and reported (2009) an appreciable increase in the container's acceleration at rotor speeds up to 20,000 rpm, larger than the stated measurement errors. In a subsequent study using a ballistic method — individual acceleration measurements of about 40 ms, repeated at intervals of 0.5 to 1.0 minute — he reported that over the rotor frequency range of roughly 20–400 Hz the changes in free-fall acceleration were predominantly negative, with apparently "resonant" maxima and minima at particular frequencies.

Dmitriev takes these data to indicate an inequality of inertial and gravitational mass, and hence a limit on the universality of free fall. He has proposed that rotating test bodies could be used deliberately as a tool, advocating high-resolution ballistic gravimetry and "high-frequency gravimetry" using rotors as a route to greater sensitivity in gravitational measurement.

Related experiments and interpretation

Dmitriev's earlier papers explored adjacent effects with the same underlying question: whether external influences or the state of motion of a body can modify its weight. These include work on the influence of external elastic (electromagnetic) forces on gravity (2001), the weighing of a mechanical gyroscope with the spin axis oriented horizontally versus vertically (2001, with Snegov), and an asymmetry between the coefficients of restitution for vertical and horizontal quasi-elastic impacts of a ball against a massive plate (2002) — which he interpreted as evidence for an anisotropy of the inertial mass of a body in the Earth's gravitational field. He has described this programme collectively as "dynamic weighing," and has argued that it points toward a phenomenological physics of gravitation in which an analogue of Lenz's rule operates: a change imposed on a body produces a gravitational response opposing that change.

His work is published largely outside the mainstream gravitational-physics literature, in the general physics category of arXiv and in conference proceedings, and the effects he reports have not been confirmed by independent groups. Dmitriev's own position is that the experiments are straightforward, repeatable and cheap enough to be checked, and that the reluctance to check them reflects confidence in theory rather than the state of the evidence.

Discussed in CNPS talks

His experimental gravity results are among those cited in CNPS discussions of alternative gravity theories:

• "Electrostatic (Capacitance) Gravity Theory with Dr. Dennis J. Allen Jr." (2 September 2023)

Abstracts

• 2013 - "Frequency Dependence of Rotors Free Falling Acceleration and Inequality of Inertial and Gravity Masses"
• 2011 - "Experimental Confirmation of the Gravitation Force Negative Temperature Dependence" (Read in full)
• 2011 - "Frequency Dependence of Rotor's Free Falling Acceleration and Inequality of Inertial and Gravity Masses" (Read in full)
• 2010 - "Dynamic Weighing Experiments - the Way to New Physics of Gravitation" (Read in full)
• 2006 - "Interesting Problems Concerning the Inhomogeneous Physical Vacuum"

Works

• A. L. Dmitriev, “On the Influence of the External Elastic (Electromagnetic) Forces on the Gravity”, Russian Physics Journal, Vol. 44, No 12, 1323 (2001).
• A. L. Dmitriev and V. S. Snegov, “The Weighing of a Mechanical Gyroscope with Horizontal and Vertical Orientation of the Spin Axis”, Measurement Techniques, Vol. 44, No 8, 831 (2001).
• A. L. Dmitriev, “Inequality of the Coefficients of Restitution for Vertical and Horizontal Quasielastic Impacts of a Ball Against a Massive Plate”, International Applied Mechanics. Vol. 3, No 6, 747 (2002).
• A. L. Dmitriev, E. M. Nikushchenko and V. S. Snegov, “Influence of the Temperature of Body on Its Weight”, Measurement Techniques, Vol. 46, No 2, 115 (2003).
• A. L. Dmitriev, “Temperature Dependence of Gravitational Force: Experiments, Astrophysics, Perspectives”, arXiv:physics/0611173 (2006).
• A. L. Dmitriev, “Measurements of the Influence of Acceleration and Temperature of Bodies on Their Weight”, AIP Conference Proc., Vol. 969, 1163 (2008); arXiv:0803.1730.
• A. L. Dmitriev, “Analogue of Lenz's Rule in Phenomenological Gravitation”, AIP Conference Proc., Vol. 1103, 345 (2009).
• A. L. Dmitriev, “On the Experimental Substantiation of Anisotropy of Inertial Mass of Body in the Earth Gravitation Field”, arXiv:0903.4433 (2009).
• A. L. Dmitriev, E. M. Nikushchenko and S. A. Bulgakova, “Nonzero Result of Measurement of Acceleration of Free Falling Gyroscope with the Horizontal Axis”, arXiv:0907.2790 (2009).
• A. L. Dmitriev, E. M. Nikushchenko and S. A. Bulgakova, “Dynamic Weighing Experiments – the Way to New Physics of Gravitation”, AIP Conference Proc., Vol. 1208, 237 (2010).
• A. L. Dmitriev, “Frequency Dependence of Rotor's Free Falling Acceleration and Inequality of Inertial and Gravity Masses”, arXiv:1101.4678 (2011).
• A. L. Dmitriev, “Experimental Confirmation of the Gravitation Force Negative Temperature Dependence”, arXiv:1105.2666 (2011).
• A. L. Dmitriev, “Simple Experiment Confirming the Negative Temperature Dependence of Gravity Force”, arXiv:1201.4461 (2012).
• A. L. Dmitriev, “Thermogravimetry and the Negative Temperature Dependence of Gravity”, Applied Physics Research, Vol. 7, No 6, 43 (2015).
• A. L. Dmitriev, “Prospects of High-Frequency Gravimetry”, INASE conference proceedings, Vienna (2015).

External links

• arXiv listing for A. L. Dmitriev
• "Experimental Confirmation of the Gravitation Force Negative Temperature Dependence" on ResearchGate
• "Thermogravimetry and the Negative Temperature Dependence of Gravity", Applied Physics Research (2015)