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We propose a two-qubit gate based on dipolar exchange interactions between individually addressable ultracold polar molecules in an array of optical dipole traps. Our proposal treats the full Hamiltonian of the Σ molecule NaCs, utilizing a pair of nuclear spin states as storage qubits. A third rotationally excited state with rotation-hyperfine coupling enables switchable electric dipolar exchange interactions between two molecules to generate an iSWAP gate. All three states are insensitive to external magnetic and electric fields. Impacts on gate fidelity due to coupling to other molecular states, imperfect ground-state cooling, blackbody radiation and vacuum spontaneous emission are small, leading to potential fidelity above 99.99% in a coherent quantum system that can be scaled by purely optical means.
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http://dx.doi.org/10.1039/c8sc02355g | DOI Listing |
J Phys Chem A
September 2025
Department of Chemistry, Institute for Quantum Information Research and Engineering, and Center for Molecular Quantum Transduction, Northwestern University, Evanston, Illinois 60208-3113, United States.
Light-driven formation of radical ion pairs that occurs much faster than their electron spin dynamics results in correlated spins whose coherence properties can be used as a quantum-based electric field sensor. This results from the radical ion pair having charge and spin distributions that track one another. Thus, electric field induced changes in the distance between the two charges are reflected in the spin-spin distance that can be measured directly using out-of-phase electron spin echo envelope modulation (OOP-ESEEM), a pulse-EPR technique.
View Article and Find Full Text PDFJ Phys Chem Lett
September 2025
The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China.
Dynamic nuclear polarization (DNP) has emerged as a powerful technique to overcome the sensitivity limit of solid-state nuclear magnetic resonance (ssNMR) spectroscopy through polarizing agents (PAs) carrying unpaired electrons. Nitroxide biradical-based PAs have garnered great attention due to their superior DNP performance. Here, we report TJPols─water-soluble acrylamide-linked nitroxide biradicals featuring facile large-scale synthesis.
View Article and Find Full Text PDFNano Lett
September 2025
School of Physics, Hubei Key Laboratory of Gravitation and Quantum Physics, Institute for Quantum Science and Engineering, Huazhong University of Science and Technology, 430074 Wuhan, China.
Dipolar coupling between closely spaced magnetic waveguides enables magnonic directional couplers serving as signal combiners, power splitters, demultiplexers, and more. The wavelength-dependent coupling, combined with the weak nonlinear variation of spin-wave wavelength at constant frequency, introduces power-dependent characteristics of directional couplers. This property has been utilized in magnonic logic elements and other applications.
View Article and Find Full Text PDFAcc Chem Res
August 2025
Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
ConspectusAdiabatic demagnetization refrigeration (ADR), which exploits the magnetocaloric effect (MCE), remains the only helium-free refrigeration technology capable of reaching temperatures below 1 K. With the rapid growth of quantum computing and astronomical observation, there is a pressing need for large-capacity ADR systems─underscoring the critical demand for magnetic refrigerants capable of generating substantial magnetic entropy changes (-Δ) at millikelvin temperatures. However, a long-standing challenge persists: achieving both large -Δ values and low magnetic ordering temperatures ().
View Article and Find Full Text PDFJ Mol Biol
August 2025
Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA. Electronic address:
Heteronuclear NMR methodologies developed over the past 40 years have enabled atomic level insights into the solution-state structure and dynamics of proteins of ever-increasing size, some as large as 1 MDa. Unfortunately, H-C and H-N correlated methods foundational for studies of proteins have been less useful when applied to larger RNAs (>50 nucleotides; ∼17 kDa) due primarily to adverse relaxation effects caused by strong H-C dipolar coupling and difficulties obtaining and assigning H-N correlated spectra for exchangeable protons. Recently, alternative homo- and heteronuclear NMR approaches have been developed that involve nucleotide- and sequence-specific isotopic labeling.
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