109 research outputs found
Producing cluster states in charge qubits and flux qubits
We propose a method to efficiently generate cluster states in charge qubits,
both semiconducting and superconducting, as well as flux qubits. We show that
highly-entangled cluster states can be realized by a `one-touch' entanglement
operation by tuning gate bias voltages for charge qubits. We also investigate
the robustness of these cluster states for non-uniform qubits, which are
unavoidable in solid-state systems. We find that quantum computation based on
cluster states is a promising approach for solid-state qubits.Comment: 4 pages, 1 figure
Dynamics and Control of a Quasi-1D Spin System
We study experimentally a system comprised of linear chains of spin-1/2
nuclei that provides a test-bed for multi-body dynamics and quantum information
processing. This system is a paradigm for a new class of quantum information
devices that can perform particular tasks even without universal control of the
whole quantum system. We investigate the extent of control achievable on the
system with current experimental apparatus and methods to gain information on
the system state, when full tomography is not possible and in any case highly
inefficient
Stimulated wave of polarization in spin chains
Stimulated wave of polarization, triggered by a flip of a single spin,
presents a simple model of quantum amplification. Previously, it has been found
that such wave can be excited in a 1D Ising chain with nearest-neighbor
interactions, irradiated by a weak resonant transverse field. Here we explore
models with more realistic Hamiltonians, in particular, with natural
dipole-dipole interactions. Results of simulations for 1D spin chains and rings
with up to nine spins are presented.Comment: 15 pages, 5 figure
Amplitudes and time scales of picosecond-to-microsecond motion in proteins studied by solid-state NMR: a critical evaluation of experimental approaches and application to crystalline ubiquitin
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MULTIPLE-QUANTUM DYNAMICS IN NMR: A DIRECTED WALK THROUGH LIOUVILLE SPACE
A guide to quantifying membrane protein dynamics in lipids and other native-like environments by solution-state NMR spectroscopy
Recent biochemical and technical developments permit residue-specific solution NMR measurements of membrane protein (MP) dynamics in lipidic and chaperone-bound environments. This is possible by combinations of improved sample preparations with suitable NMR relaxation experiments to correlate protein function to backbone dynamics on timescales from picoseconds to seconds, even for large MP-lipid assemblies above 100 kDa in molecular mass. Here, we introduce the basic concepts of different NMR relaxation experiments, individually sensitive to specific timescales. We discuss the general limitations of detergent environments and highlight the importance for native-like environments when studying MPs. We then review three practical studies of fast- and slow-timescale MP dynamics in lipid environments, as well as in a natively unfolded, chaperone-bound state. These examples illustrate the new avenues solution NMR spectroscopy is taking to investigate MP dynamics in native-like environments with atomic resolution
A guide to quantifying membrane protein dynamics in lipids and other native‐like environments by solution‐state NMR
Theoretical study of the nonlinear optical properties of potassium titanyl phosphate (KTiOPO4): cooperative effects in extended --Ti--O--Ti--O-- chains
Two-dimensional rotational spin-echo nuclear magnetic resonance in solids: correlation of chemical shift and dipolar interactions
Two-dimensional NMR techniques which sep. the chem. shift and heteronuclear dipolar interactions were applied to samples spinning at the magic angle. Because of the inhomogeneous nature of the 2 interactions, rotational echoes were obsd. in the time domain of each dimension. The corresponding Fourier transforms yield rotational sideband spectra which provide information on the principal values and relative orientations of the shift and dipolar tensors, and from the latter, internuclear distances may be calcd. The techniques therefore provide a means for obtaining structural data, for example, 13C-1H and 15N-1H distances, in powder samples. [on SciFinder (R)
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