48,921 research outputs found
Lab-frame observables for probing the top-Higgs interaction
We investigate methods to explore the CP nature of the coupling
at the LHC, focusing on associated production of the Higgs with a
pair. We first discuss the constraints implied by low-energy observables and by
the Higgs-rate information from available LHC data, emphasizing that they
cannot provide conclusive evidence on the nature of this coupling. We then
investigate kinematic observables that could probe the coupling
directly, in particular quantities that can be constructed out of just
lab-frame kinematics. We define one such observable by exploiting the fact that
spin correlations do also carry information about the CP-nature of
the coupling. Finally, we introduce a CP-odd quantity and a
related asymmetry, able to probe CP violation in the coupling and
likewise constructed out of lab-frame momenta only.Comment: 32 pages, updated with latest data from ATLAS and references adde
Partial-measurement back-action and non-classical weak values in a superconducting circuit
We realize indirect partial measurement of a transmon qubit in circuit
quantum electrodynamics by interaction with an ancilla qubit and projective
ancilla measurement with a dedicated readout resonator. Accurate control of the
interaction and ancilla measurement basis allows tailoring the measurement
strength and operator. The tradeoff between measurement strength and qubit
back-action is characterized through the distortion of a qubit Rabi oscillation
imposed by ancilla measurement in different bases. Combining partial and
projective qubit measurements, we provide the solid-state demonstration of the
correspondence between a non-classical weak value and the violation of a
Leggett-Garg inequality.Comment: 5 pages, 4 figures, and Supplementary Information (8 figures
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