Efficient Code for Relativistic Quantum Summoning

Summoning retrieves quantum information, prepared somewhere in spacetime, at another specified point in spacetime, but this task is limited by the quantum no-cloning principle and the speed-of-light bound. We develop a thorough mathematical framework for summoning quantum information in a relativistic system and formulate a quantum summoning protocol for any valid configuration of causal diamonds in spacetime. For single-qubit summoning, we present a protocol based on a Calderbank-Shor-Steane code that decreases the space complexity for encoding by a factor of two compared to the previous best result and reduces the gate complexity from scaling as the cube to the square of the number of causal diamonds. Our protocol includes decoding whose gate complexity scales linearly with the number of causal diamonds. Our thorough framework for quantum summoning enables full specification of the protocol, including spatial and temporal implementation and costs, which enables quantum summoning to be a well posed protocol for relativistic quantum communication purposes.Comment: 15 pages, 7 figure

Singular continuous spectrum is generic

In a variety of contexts, we prove that singular continuous spectrum is generic in the sense that for certain natural complete metric spaces of operators, those with singular spectrum are a dense $G_\delta$.Comment: 5 page

Nuclear-nuclear interaction mediated by a mechanically controlled nitrogen-vacancy-center spin in diamond

We propose a scheme to achieve nuclear-nuclear indirect interactions mediated by a mechanically driven nitrogen-vacancy (NV) center in diamond. Here we demonstrate two-qubit entangling gates and quantum-state transfer between two carbon nuclei in diamond. In such a system, the NV center interacts with a nearby nuclear spin via a dipole-dipole interaction. Under the quantum Zeno condition, the scheme is robust against decoherence caused by coupling between the NV center (nuclear spins) and the environment. Conveniently, precise control of dipole coupling is not required so this scheme is insensitive to fluctuating positions of the nuclear spins and the NV center. Our scheme provides a general blueprint for multi-nuclear-spin gates and for multi-party communication in a polygon geometry with each vertex occupied by a nuclear spin.Comment: 11 pages, 8 figure

Efficient code for relativistic quantum summoning

Summoning retrieves quantum information, prepared somewhere in spacetime, at another specified point in spacetime, but this task is limited by the quantum no-cloning principle and the speed-of-light bound. We develop a thorough mathematical framework for summoning quantum information in a relativistic system and formulate a quantum summoning protocol for any valid configuration of causal diamonds in spacetime. For single-qubit summoning, we present a protocol based on a Calderbank–Shor–Steane code that decreases the space complexity for encoding by a factor of two compared to the previous best result and reduces the gate complexity from scaling as the cube to the square of the number of causal diamonds. Our protocol includes decoding whose gate complexity scales linearly with the number of causal diamonds. Our thorough framework for quantum summoning enables full specification of the protocol, including spatial and temporal implementation and costs, which enables quantum summoning to be a well posed protocol for relativistic quantum communication purposes

Potential for interdependent development of tRNA determinants for aminoacylation and ribosome decoding.

Although the nucleotides in tRNA required for aminoacylation are conserved in evolution, bacterial aminoacyl-transfer RNA synthetases are unable to acylate eukaryotic tRNA. The cross-species barrier may be due to the absence of eukaryote-specific domains from bacterial aminoacyl-transfer RNA synthetases. Here we show that whereas Escherichia coli CysRS cannot acylate human tRNA(Cys), the fusion of a eukaryote-specific domain of human CysRS overcomes the cross-species barrier in human tRNA(Cys). In addition to enabling recognition of the sequence differences in the tertiary core of tRNA(Cys), the fused eukaryotic domain redirects the specificity of E. coli CysRS from the A37 present in bacterial tRNA(Cys) to the G37 in mammals. Further experiments show that the accuracy of codon recognition on the ribosome was also highly sensitive to the A37G transition in tRNA(Cys). These results raise the possibility of the development of tRNA nucleotide determinants for aminoacylation being interdependent with those for ribosome decoding

Temporal Target Restriction of Olfactory Receptor Neurons by Semaphorin-1a/PlexinA-Mediated Axon-Axon Interactions

SummaryAxon-axon interactions have been implicated in neural circuit assembly, but the underlying mechanisms are poorly understood. Here, we show that in the Drosophila antennal lobe, early-arriving axons of olfactory receptor neurons (ORNs) from the antenna are required for the proper targeting of late-arriving ORN axons from the maxillary palp (MP). Semaphorin-1a is required for targeting of all MP but only half of the antennal ORN classes examined. Sema-1a acts nonautonomously to control ORN axon-axon interactions, in contrast to its cell-autonomous function in olfactory projection neurons. Phenotypic and genetic interaction analyses implicate PlexinA as the Sema-1a receptor in ORN targeting. Sema-1a on antennal ORN axons is required for correct targeting of MP axons within the antennal lobe, while interactions amongst MP axons facilitate their entry into the antennal lobe. We propose that Sema-1a/PlexinA-mediated repulsion provides a mechanism by which early-arriving ORN axons constrain the target choices of late-arriving axons

Efficient code for relativistic quantum summoning

Summoning retrieves quantum information, prepared somewhere in spacetime, at another specified point in spacetime, but this task is limited by the quantum no-cloning principle and the speed-of-light bound. We develop a thorough mathematical framework for summoning quantum information in a relativistic system and formulate a quantum summoning protocol for any valid configuration of causal diamonds in spacetime. For single-qubit summoning, we present a protocol based on a Calderbank–Shor–Steane code that decreases the space complexity for encoding by a factor of two compared to the previous best result and reduces the gate complexity from scaling as the cube to the square of the number of causal diamonds. Our protocol includes decoding whose gate complexity scales linearly with the number of causal diamonds. Our thorough framework for quantum summoning enables full specification of the protocol, including spatial and temporal implementation and costs, which enables quantum summoning to be a well posed protocol for relativistic quantum communication purposes