Sadao Nakajima

Bibliometric databases give 65 papers with about 3.4k citations and 2 hit papers; the Rankless profile reports an h-index of 16 with 2.5k indexed citations, while the Exa record reports h-index 18 and 3,401 citations, an unresolved disagreement between the two databases^{3 • 4}. The 1958 transport paper is his most-cited work, with 1,083 indexed citations on Rankless against 1,481 on Exa; the 1957 Kubo–Yokota–Nakajima paper follows with 508^{3 • 4}. Other cited works include The Physics of Elementary Excitations (Springer, 1980, with Yutaka Toyozawa and Ryuzo Abe), the 1973 paramagnon paper (76), and the 1963 electron-phonon papers with Watabe (57 and 17)³. By research area, his most-cited clusters are superconductivity and magnetism (14 papers), laser-induced spectroscopy and plasma (9), and quantum and superfluid helium dynamics (8), and his work is most cited in atomic and molecular physics and statistical physics³.

Scientific work

Steady diffusion. His 1958 paper "On Quantum Theory of Transport Phenomena", received August 17, 1958 at Nagoya University's Physical Institute and published in Progress of Theoretical Physics Vol. 20, No. 6, pp. 948–959, formulates the quantum statistical mechanics of steady diffusion as the most natural generalization of the Bloch kinetic equation^{1 • 4}. The method seeks a steady solution of Liouville's equation, with the boundary condition fixed by requiring the solution to lead to a given distribution of average density⁵. The theory generalizes the Bloch equation to strongly interacting particles, reducing to it for weakly interacting particles, by extending a damping-theoretical expansion of Kohn and Luttinger⁴. Its key conclusion concerns the Einstein relation: the full text states it is valid only for the symmetric part of the diffusion- and electric-conductivity tensors, so for the Hall effect the gradient of chemical potential is not equivalent to the electric field, a difference first suggested by Kasuya and appreciable at low temperatures and strong magnetic fields⁴. The paper's own summary, however, reads "antisymmetric part" where the full text reads "symmetric", an unresolved discrepancy within the primary document¹.

Gauge invariance and superconductivity. In a paper dated November 26, 1958 at Nagoya and published in February 1959, Nakajima addressed the gauge-invariant Meissner effect. Following Bardeen's suggestion and Anderson's emphasis that plasma excitations must be included, he showed that taking account of collective excitations yields the gauge-invariant result, and that the non-gauge-invariant term in BCS theory introduces only a minor error in the normal part of the diamagnetic current². The paper applies Tomonaga's method to split the Hamiltonian and the electron momentum density into collective and individual modes, and acknowledges Professor Matsubara and Dr. Yosida for discussions².

Linear response and later topics. The 1957 paper "Statistical-Mechanical Theory of Irreversible Processes. II. Response to Thermal Disturbance", written with Ryogo Kubo and Mario Yokota in the Journal of the Physical Society of Japan, is his second most-cited work³. Later work included the electron-phonon interaction in normal metals (two 1963 papers with Mitsuo Watabe) and the paramagnon effect on the BCS transition in He3 (PTP, 1973); the wiki-mirror source credits him with introducing paramagnons into the theory of superfluid He3 and with work on electron-phonon interaction as a basis of superconductivity theory³.

Place among his contemporaries

Co-authorship with Kubo and Yokota places Nakajima in the Japanese statistical-mechanics circle around Ryogo Kubo; his frequent co-authors also include Ryuzo Abe, Yutaka Toyozawa, Mitsuo Watabe, Kiichiro Kagawa, Daijiro Yoshioka, Yoshimasa Murayama, Hiromichi Suzuki, and Takao Saruta³. His use of Tomonaga's method in the Meissner-effect paper, and his acknowledgments to Matsubara and Yosida, tie him to the wider postwar Japanese theoretical-physics community².

Legacy and influence

Conference leadership. He also co-edited, with Masato Murakami, the proceedings of the 9th International Symposium on Superconductivity (ISS 96), held October 21–24, 1996 in Sapporo⁶.

References

1. Sadao Nakajima, On Quantum Theory of Transport Phenomena, Progress of Theoretical Physics 20(6):948 (1958), full-text PDF
2. Sadao Nakajima, On the Gauge-Invariant Meissner Effect, Progress of Theoretical Physics (1959), full-text record
3. Rankless author profile: Sadao Nakajima
4. On Quantum Theory of Transport Phenomena, PTP 20(6), 948–959 (1958), Exa record
5. On Quantum Theory of Transport Phenomena: Steady Diffusion, INSPIRE-HEP record
6. Advances in Superconductivity IX Vol. 2 (ISS 96 proceedings), ed. Nakajima and Murakami, publisher record

Topic: Encyclopedia › Physical world and mathematics › Physical and mathematical scientists › Physicists and astronomers › Researchers in condensed matter physics and quantum materials

Initially written Oct 10, 2026 · Edited: Oct 11, 2026; Oct 15, 2026; Oct 25, 2026

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