In contrast to classical physics, quantum theory demands that not all properties can be simultaneously well defined; the Heisenberg uncertainty principle is a manifestation of this fact. Alternatives have been explored--notably theories relying on joint probability distributions or non-contextual hidden-variable models, in which the properties of a system are defined independently of their own measurement and any other measurements that are made. Various deep theoretical results imply that such theories are in conflict with quantum mechanics. Simpler cases demonstrating this conflict have been found and tested experimentally with pairs of quantum bits (qubits). Recently, an inequality satisfied by non-contextual hidden-variable models and violated by quantum mechanics for all states of two qubits was introduced and tested experimentally. A single three-state system (a qutrit) is the simplest system in which such a contradiction is possible; moreover, the contradiction cannot result from entanglement between subsystems, because such a three-state system is indivisible. Here we report an experiment with single photonic qutrits which provides evidence that no joint probability distribution describing the outcomes of all possible measurements--and, therefore, no non-contextual theory--can exist. Specifically, we observe a violation of the Bell-type inequality found by Klyachko, Can, Binicioğlu and Shumovsky. Our results illustrate a deep incompatibility between quantum mechanics and classical physics that cannot in any way result from entanglement.
We study three ͑nested, parallel, and sequential cascade͒ types of schemes for doubly dressed four-wavemixing processes in an open five-level atomic system. The interaction between two dressing fields of the nested-cascade scheme is strongest and weakest for the parallel-cascade scheme, with the sequential scheme intermediate between them. Mutual-dressing processes and constructive or destructive interference between two coexisting dressed multiwave mixing channels in such a system are also considered. Investigations of these multidressing mechanisms and interactions are very useful to understand and control the generated high-order nonlinear optical signals.
Two novel drug−drug (1:1) cocrystals of berberine chloride (BER) with myricetin (MYR) and dihydromyricetin (DMY), BER-MYR(1), and BER-DMY(2) have been prepared and investigated systematically. The O−H•••Cl − intermolecular interactions formed by hydroxyl groups of MYR and DMY with chloride anion dominated the formation of cocrystals 1 and 2. The values of energy gap (ΔE) and electrophilicity index (ω) computed by density functional theory calculations confirmed the chemical stability of molecules. Both cocrystals revealed low moisture adsorption up to 95% of relative humidity. The myricetin in cocrystal 1 revealed enhanced solubility in water. The two drugs in BER-MYR and BER-DMY cocrystals show synergistic anticancer effect in vitro.
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