kapralova_zdanska_2025

P. R. Kaprálová-Žďánská, “Coherent superposition mediating energy flow between fundamental and third-harmonic modes”, Phys. Rev. A 111, 043105 (2025)

Source record · Catalogue · Review register

DOI: 10.1103/PhysRevA.111.043105

Source kind: theory

Recorded technique: Non-Hermitian Floquet theory of two bound S states coupled through the continuum: a two-by-two effective Floquet Hamiltonian (Eqs. 21-27) with a formal two-photon Rabi frequency from counter-rotating terms and complex (ionisation) widths; checked against full-dimensional complex-scaled Floquet calculations of He (exponentially tempered Gaussian basis ExTG5G, L_max = 2, singly excited bound and continuum states, scaling angles theta = 0.2-0.4) for linear polarisation near 120.3 nm and up to 7.5 TW/cm^2, fitted three ways (quasi-energy splits, Sec. III; resonant-beat laser parameters, Sec. IV B; diabatic quasi-energy surfaces, Sec. IV C).

Materials in structured entries: None recorded.

Dataset quantities: None recorded.

Contents: 0 datasets; 0 formulas.

Curation notes

THE LIBRARY COPY is the author’s manuscript (ResearchGate), not the version of record: 99 PDF pages, pp. 1-67 the article and pp. 68-99 ‘Supplementary Material’ I and II; no journal reference on it, and its title reads ‘Coherent superposition mediating energy flow between the fundamental and the third harmonic mode’ (the published title is the citation’s). Pages are PDF pages. Values may differ from the published version; not checked against it.

NOTHING TAKEN (the maintainer, 2026-10-08, TC-872): the coefficients of Table I stay in these notes. Table I (p. 51, tbl_ebf0fb433ade, checked against the image; merged cells), the effective Hamiltonian’s parameters at I_0 = 0 from the three fits (no star: Sec. III; *: Sec. IV C; **: Sec. IV B): |mu_0| = 2.03 a.u. (2.03*, 2.02**), d|mu_0| /dI_0 = 0.9e-3 a.u./(TW cm^-2) (-1e-3*); arg mu_0 = 3e-3 rad (2e-4*); gamma = 25.5 microE_h/(TW cm^-2) (25.7*, 25.9**); delta_omega = 58 (61*, 60.9**) microE_h/(TW cm^-2); gamma_1s2 = -0.2 (0) (-0.3* (0)) and gamma_1s2s = 25.3 (25.4*) microE_h/(TW cm^-2). The text gives gamma_1s2s = 25.2 +- 0.2 microE_h/(TW cm^-2) for the Sec. IV C fit (p. 44), against Table I’s 25.4*; the negative gamma_1s2 is ‘clearly a numerical artifact’, probably below 1 microE_h/(TW cm^-2) (p. 44).

CONVENTIONS. The 2 x 2 Floquet Hamiltonian is (hbar/2) [[-Delta, Omega], [Omega, Delta]] (Eq. 24): the off-diagonal is hbar Omega/2, with hbar Omega = kappa I_0 (Eq. 27), kappa = mu_0 sqrt(2/(c eps_0)) (Eq. 80; Omega = mu_0 I_0 sqrt(2/(c eps_0)), Eq. 81). The diabatic quasi-energies carry I_0 (delta_omega - i gamma/2) (Eqs. 25-26) with bound-state widths written E - i Gamma/2 (Eq. 28): gamma I_0 is a full width, and the population of 1s2s decays at gamma_1s2s I_0/hbar (Eq. 109: ‘gamma I_0/2 hbar determines the average ionization rate over the Rabi cycle’, half the time in each state). Appendix F (p. 61) prints ‘I_0[TW/cm^2] = 2.84937923 x 10^-5 I_0[a.u.]’ and sqrt(2/(c eps_0)) = 0.428255165 a.u.; the paper uses the first as I_0[a.u.] = 2.84937923e-5 x I_0[TW/cm^2] (an atomic unit of intensity of 3.5095e16 W/cm^2, the intensity of a unit field E_0 with I = (1/2) eps_0 c E_0^2): with it Eq. 110 reproduces the printed a = 0.52 (0.515 from gamma = 25.5 and mu_0 = 2.03; computed 2026-10-08); read as printed it would not.

THE IMPLIED 1s2s PHOTOIONISATION CROSS SECTION (computed 2026-10-08, not data): Gamma = gamma_1s2s I_0/hbar = 25.3e-6 E_h / hbar = 25.3e-6 / 2.41888e-17 s = 1.0459e12 s^-1 per TW/cm^2; the photon at 120.3 nm is 10.3063 eV, Phi = 1e12/(10.3063 x 1.602177e-19) = 6.0563e29 cm^-2 s^-1 per TW/cm^2; sigma = 1.727e-18 cm^2 = 1.73 Mb (1.720 and 1.734 for 25.2 and 25.4). kumar_2026’s Gamma_e gives 1.691e-18 cm^2 at 120.27 nm: this is 2.1 % higher; gamma is not a half-width (no factor 2). In kumar_2026’s units (E_0^2 in a.u., I_0[a.u.] = E_0^2): gamma_1s2s = 0.8879 E_0^2 against kumar_2026’s Gamma_e = 0.869215 E_0^2, and the coupling Omega = 2.03 x 0.428255 E_0^2 = 0.8694 E_0^2 (0.8651 for 2.02**) against kumar_2026’s Omega_ge^P = 0.886278 E_0^2 (1.9 % apart); both papers put Omega/2 off the diagonal. Each of Kumar’s two coefficients is closer to the other paper’s other one (0.869215 against 0.8694, 0.02 %; 0.886278 against 0.8879, 0.2 %): see the register.

OTHER CONTENT, NOT TAKEN: the exceptional-point and Rabi-cycle analysis (Secs. II C-E, V; a = 0.52 +- 0.01, phi = -(0.345 +- 0.01) pi, cot(phi/2) = 1.65 +- 0.05, Eq. 111, p. 47), third-harmonic emission, and the femtosecond Rabi cycling of Fig. 19 (with 1s2 -> 1s2p and 1s4p one-photon comparisons), figures and model parameters only.

FURTHER TWO-PHOTON DATA CITED: none with values; the He basis sets and earlier strong-field calculations are the author’s (Refs. 47-48).

Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.

Datasets

No datasets are recorded.

Formulas

No formulas are recorded.

Corrections

No dataset errata are recorded in this source record.

Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the review register for the checks and decisions.