Exceptional Entanglement Phenomena: Non-Hermiticity Meeting Nonclassicality.

Non-Hermitian (NH) extension of quantum-mechanical Hamiltonians represents one of the most significant advancements in physics. During the past two decades, numerous captivating NH phenomena have been revealed and demonstrated, but all of which can appear in both quantum and classical systems. This leads to the fundamental question: what NH signature presents a radical departure from classical physics? The solution of this problem is indispensable for exploring genuine NH quantum mechanics, but remains experimentally untouched so far. Here, we resolve this basic issue by unveiling distinct exceptional entanglement phenomena, exemplified by an entanglement transition, occurring at the exceptional point of NH interacting quantum systems. We illustrate and demonstrate such purely quantum-mechanical NH effects with a naturally dissipative light-matter system, engineered in a circuit quantum electrodynamics architecture. Our results lay the foundation for studies of genuinely quantum-mechanical NH physics, signified by exceptional-point-enabled entanglement behaviors.

Deterministic Entanglement Swapping in a Superconducting Circuit.

Entanglement swapping, the process to entangle two particles without coupling them in any way, is one of the most striking manifestations of the quantum-mechanical nonlocal characteristic. Besides fundamental interest, this process has applications in complex entanglement manipulation and quantum communication. Here we report a high-fidelity, unconditional entanglement swapping experiment in a superconducting circuit. The measured concurrence characterizing the qubit-qubit entanglement produced by swapping is above 0.75, confirming most of the entanglement of one qubit with its partner is deterministically transferred to another qubit that has never interacted with it. We further realize delayed-choice entanglement swapping, showing whether two qubits previously behaved as in an entangled state or as in a separable state is determined by a later choice of the type of measurement on their partners. This is the first demonstration of entanglement-separability duality in a deterministic way.

Rice OsHsp16.9A interacts with OsHsp101 to confer thermotolerance.

Class I small heat shock proteins (CI sHSPs), OsHsp16.9A and OsHsp18.0, share 74% identity in amino acid sequences and accumulate in response to heat shock treatments. Individual rice transformants overexpressing OsHsp16.9A and OsHsp18.0 exhibit distinct thermoprotection/thermotolerance modes. Under high temperature stress, OsHsp16.9A-overexpressing lines showed higher seed germination rate, seedling survival, and pollen germination than wild-type controls, while OsHsp18.0 overexpression provided higher thermoprotection/thermotolerance for seedling survival. To elucidate the functional roles of OsHsp16.9A, mass spectrometry was used to identify OsHsp16.9A-interacting proteins. OsHsp101 was consistently identified in the OsHsp16.9A protein complex in several mass spectrometry analyses of seed proteins from OsHsp16.9A-overexpressing lines. Both OsHsp16.9A and OsHsp101 proteins accumulated during similar developmental stages of rice seeds and formed a heat-stable complex under high temperature treatments in in vitro assays. Co-localization of OsHsp16.9A and OsHsp101 was observed via ratiometric bimolecular fluorescence complementation analyses. Amino acid mutation studies revealed that OsHsp16.9A glutamate residue 74 and amino acid residues 23-36 were essential for OsHsp16.9A-OsHsp101 interaction. Moreover, overexpressing OsHsp16.9A in OsHsp101 knockdown mutants did not increase the seed germination rate under heat stress, which further confirmed the functional roles of OsHsp16.9A-OsHsp101 interaction in conferring thermotolerance to rice plants.

Cloning of a putative hypersensitive induced reaction gene from wheat infected by stripe rust fungus.

The hypersensitive response (HR) is one of the most efficient forms of plant defense against biotrophic pathogens and results in localized cell death and the formation of necrotic lesions. In this study, a novel putative hypersensitive induced reaction (HIR) gene from wheat leaves infected by incompatible stripe rust pathogen CY23, designated as Ta-hir1, was identified by using rapid amplification of cDNA ends (RACE). Ta-hir1 encodes 284 amino acids, with a predicted molecular mass of 31.31 KDa. A phylogenetic analysis showed that Ta-hir1 was highly homologous to Hv-hir1 from barley at both cDNA and deduced amino-acid levels. Amino-acid sequence analysis of the wheat HIR protein indicated the presence of the SPFH (Stomatins, Prohibitins, Flotillins and HflK/C) protein domain typical for stomatins which served as a negative regulator of univalent cation permeability, especially for potassium. The expression profile of the Ta-hir1 transcript detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time polymerase chain reaction (real time-PCR), respectively, showed that the highest expression occurred 48 h post inoculation (hpi), which is consistent with our previous histopathology observations during the stripe rust fungus-wheat incompatible reaction.