Experimental Test of Tracking the King Problem

In quantum theory, the retrodiction problem is not as clear as its classical counterpart because of the uncertainty principle of quantum mechanics. In classical physics, the measurement outcomes of the present state can be used directly for predicting the future events and inferring the past events which is known as retrodiction. However, as a probabilistic theory, quantum-mechanical retrodiction is a nontrivial problem that has been investigated for a long time, of which the Mean King Problem is one of the most extensively studied issues. Here, we present the first experimental test of a variant of the Mean King Problem, which has a more stringent regulation and is termed "Tracking the King". We demonstrate that Alice, by harnessing the shared entanglement and controlled-not gate, can successfully retrodict the choice of King's measurement without knowing any measurement outcome. Our results also provide a counterintuitive quantum communication to deliver information hidden in the choice of measurement.Comment: 16 pages, 5 figures, 2 table

Ethyl 4-anilino-3-nitrobenzoate

In the title compound, C15H14N2O4, the aromatic rings are oriented at a dihedral angle of 78.33 (3)°. An intra­molecular N—H⋯O hydrogen bond results in a non-planar six-membered ring with a flattened-boat conformation. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules. π–π contacts between the phenyl rings and both the phenyl and benzene rings, [centroid–centroid distances = 3.841 (3) and 3.961 (3) Å] may further stabilize the structure

4-Chloro-3-nitro­benzonitrile

In the title compound, C7H3ClN2O2, the Cl, C and N atoms are coplanar with the aromatic ring. In the crystal structure, weak inter­molecular C—H⋯O and C—H⋯N hydrogen bonds link the mol­ecules. The π–π contact between the benzene rings, [centroid–centroid distances = 3.912 (3) Å] may further stabilize the structure

Angular Reconstruction of a Lead Scintillating-Fiber Sandwiched Electromagnetic Calorimeter

A new method called Neighbor Cell Deposited Energy Ratio (NCDER) is proposed to reconstruct incidence position in a single layer for a 3-dimensional imaging electromagnetic calorimeter (ECAL).This method was applied to reconstruct the ECAL test beam data for the Alpha Magnetic Spectrometer-02 (AMS-02). The results show that this method can achieve an angular resolution of 7.36\pm 0.08 / \sqrt(E) \oplus 0.28 \pm 0.02 degree in the determination of the photons direction, which is much more precise than that obtained with the commonly-adopted Center of Gravity(COG) method (8.4 \pm 0.1 /sqrt(E) \oplus 0.8\pm0.3 degree). Furthermore, since it uses only the properties of electromagnetic showers, this new method could also be used for other type of fine grain sampling calorimeters.Comment: 6 pages, 8 figure

tert-Butyl N′-[4-(2-pyrid­yl)benzyl­idene]hydrazinecarboxyl­ate

In the mol­ecule of the title compound, C17H19N3O2, the aromatic rings are oriented at a dihedral angle of 3.68 (3)°. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into chains along the a axis. A weak C—H⋯π inter­action is also present