4,330 research outputs found
Hyperfine characterization and coherence lifetime extension in Pr3+:La2(WO4)3
Rare-earth ions in dielectric crystals are interesting candidates for storing
quantum states of photons. A limiting factor on the optical density and thus
the conversion efficiency is the distortion introduced in the crystal by doping
elements of one type into a crystal matrix of another type. Here, we
investigate the system Pr3+:La2(WO4)3, where the similarity of the ionic radii
of Pr and La minimizes distortions due to doping. We characterize the
praseodymium hyperfine interaction of the ground state (3H4) and one excited
state (1D2) and determine the spin Hamiltonian parameters by numerical analysis
of Raman-heterodyne spectra, which were collected for a range of static
external magnetic field strengths and orientations. On the basis of a crystal
field analysis, we discuss the physical origin of the experimentally determined
quadrupole and Zeeman tensor characteristics. We show the potential for quantum
memory applications by measuring the spin coherence lifetime in a magnetic
field that is chosen such that additional magnetic fields do not shift the
transition frequency in first order. Experimental results demonstrate a spin
coherence lifetime of 158 ms - almost three orders of magnitude longer than in
zero field.Comment: 14 pages, 6 figure
Hybrid-State Free Precession in Nuclear Magnetic Resonance
The dynamics of large spin-1/2 ensembles in the presence of a varying
magnetic field are commonly described by the Bloch equation. Most magnetic
field variations result in unintuitive spin dynamics, which are sensitive to
small deviations in the driving field. Although simplistic field variations can
produce robust dynamics, the captured information content is impoverished.
Here, we identify adiabaticity conditions that span a rich experiment design
space with tractable dynamics. These adiabaticity conditions trap the spin
dynamics in a one-dimensional subspace. Namely, the dynamics is captured by the
absolute value of the magnetization, which is in a transient state, while its
direction adiabatically follows the steady state. We define the hybrid state as
the co-existence of these two states and identify the polar angle as the
effective driving force of the spin dynamics. As an example, we optimize this
drive for robust and efficient quantification of spin relaxation times and
utilize it for magnetic resonance imaging of the human brain
Experimental realization of the Yang-Baxter Equation via NMR interferometry
The Yang-Baxter equation is an important tool in theoretical physics, with
many applications in different domains that span from condensed matter to
string theory. Recently, the interest on the equation has increased due to its
connection to quantum information processing. It has been shown that the
Yang-Baxter equation is closely related to quantum entanglement and quantum
computation. Therefore, owing to the broad relevance of this equation, besides
theoretical studies, it also became significant to pursue its experimental
implementation. Here, we show an experimental realization of the Yang-Baxter
equation and verify its validity through a Nuclear Magnetic Resonance (NMR)
interferometric setup. Our experiment was performed on a liquid state
Iodotrifluoroethylene sample which contains molecules with three qubits. We use
Controlled-transfer gates that allow us to build a pseudo-pure state from which
we are able to apply a quantum information protocol that implements the
Yang-Baxter equation.Comment: 10 pages and 6 figure
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