Pulse flip angles are calculated for three-wave mixing, three-state cycles of chiral molecules to produce optimized free induction decay amplitudes proportional to the enantiomeric excess of a sample and to produce optimized degrees of state-specific enantiomeric separation. The calculations account for the spatial degeneracy of the levels involved and the resulting inhomogeneous distribution of transition dipole moments. Cycles of transitions that include R followed by Q followed by P branch transitions display only modest reductions of the calculated optimal signals compared to those calculated if every M component was optimally polarized. Transition cycles P-Q-R are only slightly worse, while the Q-Q-Q cycles are much worse, increasingly so, as the rotational total quantum number is increased.
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http://dx.doi.org/10.1063/1.5045052 | DOI Listing |
Nanotechnology
January 2025
Departamento de Física, Universidade Federal do Ceará, Campus do Pici, Bloco 922, 60455-900, Fortaleza, 60455-900, BRAZIL.
We investigate the electronic properties of nanoribbons made out of monolayer Lieb, transition, and kagome lattices using the tight-binding model with a generic Hamiltonian. It allows us to map the evolutionary stages of the interconvertibility process between Lieb and kagome nanoribbons by means of only one control parameter. Results for the energy spectra, the density of states, and spatial probability density distributions are discussed for nanoribbons with three types of edges: straight, bearded, and asymmetric.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
New Cornerstone Science Laboratory, Department of Physics, University of Hong Kong, Hong Kong, China.
The ability to generate Landau levels using a pseudomagnetic field (PMF), also called an artificial gauge field, opens up new pathways for exploring fundamental physics and developing novel applications based on topological protection. In this Letter, we simultaneously realize a PMF and a pseudoelectric field (PEF) on a photonic crystal platform and observe a rainbow effect of the Landau zeroth modes. While a PMF induces a series of discretized Landau levels of photons in a similar way as the quantum Hall effect for electrons, a PEF breaks the degeneracy of the flat band of Landau levels over a broad range.
View Article and Find Full Text PDFJ Chem Phys
November 2024
Felix Bloch Institute for Solid State Physics, Leipzig University, Leipzig, Germany.
Structural disorder in mesoporous solids gives rise to complex phase behavior for materials confined within their pore spaces. As a result, a wide spectrum of possible phase configurations associated with spatial distributions of thermodynamic phases throughout the pore networks can be realized in experiments. Despite their importance, quantifying these states remains largely unaddressed.
View Article and Find Full Text PDFNat Nanotechnol
December 2024
Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland.
Unlocking the potential of topological order in many-body spin systems has been a key goal in quantum materials research. Despite extensive efforts, the quest for a versatile platform enabling site-selective spin manipulation, essential for tuning and probing diverse topological phases, has persisted. Here we utilize on-surface synthesis to construct spin-1/2 alternating-exchange Heisenberg chains by covalently linking Clar's goblets-nanographenes each hosting two antiferromagnetically coupled spins.
View Article and Find Full Text PDFPhys Rev Lett
September 2024
State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-electronics, Shanxi University, Taiyuan, Shanxi 030006, China.
Exceptional degeneracies and generically complex spectra of non-Hermitian systems are at the heart of numerous phenomena absent in the Hermitian realm. Recently, it was suggested that Floquet dissipative coupling in the space-time domain may provide a novel mechanism to drive intriguing spectral topology with no static analogs, though its experimental investigation in quantum systems remains elusive. We demonstrate such Floquet dissipative coupling in an ensemble of thermal atoms interacting with two spatially separated optical beams, and observe an anomalous anti-parity-time symmetry phase transition at an exception point far from the phase-transition threshold of the static counterpart.
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