Magnon-mediated qubit coupling determined via dissipation measurements

Proc. Natl. Acad. Sci. U.S.A. 121, e2313754120 (2024) · DOI: 10.1073/pnas.2313754120

License: CC BY 4.0.

Abstract

Hybrid quantum systems based on magnons promise long-range coupling between distant spin qubits, but the coupling strength is difficult to access directly. Here we show that the magnon-mediated coupling between nitrogen-vacancy center qubits can be determined from measurements of their magnon-induced relaxation. Using a Kramers-Kronig relation, the dissipative response measured through the qubit relaxation rate yields the dispersive part that sets the coherent coupling, so a single relaxation measurement determines the achievable qubit-qubit coupling in a magnonic device.

Figures

14 panels with data across 3 figures. Each panel page shows the plot, its columns and its files; each data.csv begins with a header naming the paper, the panel, the source, the license and the provenance route.

Fig. 1

Illustrative figure, no extractable data. Shown in the paper PDF.

Fig. 2

• panel (a): ODMR map of NV centers on YIG: Normalized PL against Magnetic field $\mu_0 H_{\parallel}$ (G) and Frequency (GHz). The solid line is the calculated NV transition $|0\rangle \leftrightarrow |-1\rangle$ and the dotted line the calculated surface wave plateau; the dotted vertical line marks the field where the plateau is resonant with the NV transition. data.csv
• panel (b): Longitudinal relaxation rate $\Delta(1/T_1)$ ($\mu$s$^{-1}$), referenced to its value at 600 G, against Magnetic field $\mu_0 H_{\parallel}$ (G) at $h_{\mathrm{NV}} = 400$ nm: Experiment (with YIG) and Control (without YIG), with error bars, and the Theory curve. data.csv
• panel (b-inset): Inset of printed panel (B): calculated magnon mode profiles, Mode amplitude $m_x$ (arb. units) against normalized position across the YIG film, for the Surface wave and two volume waves. The print draws them sideways in a YIG cross-section, offset and with one mirrored; here they carry no offset or flip, with position on the horizontal axis. data.csv
• panel (c-1): Sub-plot 1 of printed panel (C): calculated magnon dispersion at $\mu_0 H_{\parallel} = 82$ G, Frequency (GHz) against Wavenumber ($\mu$m$^{-1}$) on a log axis: Surface wave and Volume wave band edge, with a horizontal line at $f_{\mathrm{NV}}$. The gradient shading of the surface wave and the filled volume band of the print are not drawn. data.csv
• panel (c-2): Sub-plot 2 of printed panel (C): calculated noise spectrum $S(\omega)$ (arb. units) against Frequency (GHz) at $\mu_0 H_{\parallel} = 82$ G, with a vertical line at $f_{\mathrm{NV}}$. The print draws it sideways, sharing the frequency axis of the dispersion beside it; here frequency is on the horizontal axis. data.csv
• panel (c-3): Sub-plot 3 of printed panel (C): calculated magnon dispersion at $\mu_0 H_{\parallel} = 150$ G, Frequency (GHz) against Wavenumber ($\mu$m$^{-1}$) on a log axis: Surface wave and Volume wave band edge, with horizontal lines at $f_{\mathrm{p}}$ and $f_{\mathrm{NV}}$. The gradient shading of the surface wave and the filled volume band of the print are not drawn. data.csv
• panel (c-4): Sub-plot 4 of printed panel (C): calculated noise spectrum $S(\omega)$ (arb. units) against Frequency (GHz) at $\mu_0 H_{\parallel} = 150$ G, with vertical lines at $f_{\mathrm{p}}$ and $f_{\mathrm{NV}}$. The print draws it sideways, sharing the frequency axis of the dispersion beside it; here frequency is on the horizontal axis. data.csv

Fig. 3

• panel (a): 3D plot of $\Delta(1/T_1)$ ($\mu$s$^{-1}$) against Magnetic field $\mu_0 H_{\parallel}$ (G) and NV-YIG separation $h_{\mathrm{NV}}$ (nm): Measured field scans with error bars and Calculated curves at $h_{\mathrm{NV}} = 400$, 500, 600 and 700 nm, crossed by calculated height scans at 100, 200, 300 and 400 G. The printed panel has no legend. data.csv
• panel (a-inset): Inset of printed panel (A): $\Delta(1/T_1)$ ($\mu$s$^{-1}$) against NV-YIG separation $h_{\mathrm{NV}}$ (nm) at the critical field of 82 G, Experiment with error bars and Theory. data.csv
• panel (b): $\Delta(1/T_1)$ ($\mu$s$^{-1}$) against Magnetic field $\mu_0 H_{\parallel}$ (G) under perpendicular fields $\mu_0 H_{\perp} = 0$, 30 and 50 G: measured points with error bars and calculated curves in matching colours. data.csv

Fig. 4

• panel (a): Magnon-induced self-energy $\chi / 2\pi$ (Hz) against Magnetic field $\mu_0 H_{\parallel}$ (G): measured Im($\chi$) and Re($\chi$) with error bars, the simulated Im($\chi$) and the theoretical $g_{\mathrm{eff}}(0) = \mathrm{Re}(\chi)$. Dotted horizontal lines mark zero and the 72 G value of $g_{\mathrm{eff}}(0)$, carried into panel (B). data.csv
• panel (b): Calculated coupling $g_{\mathrm{eff}}/2\pi$ (Hz) against Distance $r$ ($\mu$m) for two NV centers at $h_{\mathrm{NV}} = 400$ nm displaced along $H_{\parallel}$, at 72, 81, 82 and 83 G, with the dipole-dipole coupling (Dipole) as reference. The dotted line repeats the 72 G level of panel (A); the drawing of the two NV centers is not shown. data.csv
• panel (c): Ratio $|\mathrm{Re}(\chi)/\mathrm{Im}(\chi)|$ against Magnetic field $\mu_0 H_{\parallel}$ (G): measured (Exp. ratio, with error bars) and calculated (Calc. ratio). data.csv
• panel (d): Calculated $|g_{\mathrm{eff}}|$, normalized by $g_{\mathrm{eff}}(r = 0)$, against Distance $r$ ($\mu$m) for two YIG geometries, an infinitely long Waveguide and a Nanobar. data.csv

Cite

Masaya Fukami, Jonathan C. Marcks, Denis R. Candido, Leah R. Weiss, Benjamin Soloway, Sean E. Sullivan, Nazar Delegan, F. Joseph Heremans, Michael E. Flatte, David D. Awschalom. Magnon-mediated qubit coupling determined via dissipation measurements. Proc. Natl. Acad. Sci. U.S.A. 121, e2313754120 (2024). https://doi.org/10.1073/pnas.2313754120

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