Conversion of parahydrogen induced longitudinal two-spin order to evenly distributed single spin polarisation by optimal control pulse sequences

Bretschneider, Christian O.; Karabanov, Alexander; Nielsen, Niels Chr.; Köckenberger, Walter

doi:10.1063/1.3691193

Cited by 12 publications

(9 citation statements)

References 28 publications

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“…13 At the same time, in many CIDNP and PHIP applications it is highly desirable to have molecules with considerable net hyper-polarization, which can be difficult to achieve, for instance, by manipulating the ALTADENA or PASADENA pattern by NMR pulse sequences. Although there are successful examples of utilizing NMR pulses to control and transfer PHIP-derived spin order 5,7,[14][15][16][17][18] the need for precise synchronization of the pulses with the chemical reaction and control of coherences between the spin states can be a problem. To have at the output net hyper-polarization is especially crucial for MRI since at typical magnetic fields used in the MRI technique NMR multiplet structures as well as chemical shifts cannot be resolved with the consequence that only the integral net hyper-polarization is observable.…”

Section: Introductionmentioning

confidence: 99%

Manipulating spin hyper-polarization by means of adiabatic switching of a spin-locking RF-field

Kiryutin

Ivanov

Yurkovskaya

et al. 2013

Phys. Chem. Chem. Phys.

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We propose a technique for transferring the multiplet spin polarization (CIDNP or PHIP, or one created by any other method), which is the mutual entanglement of spins, into net hyper-polarization with respect to the direction of a high magnetic field by slowly (adiabatically) switching-off a strong external RF-field with a specially selected frequency. The net hyper-polarized molecules can then be used in NMR spectroscopy or imaging for strong signal enhancement.

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Section: Introductionmentioning

confidence: 99%

Manipulating spin hyper-polarization by means of adiabatic switching of a spin-locking RF-field

Kiryutin

Ivanov

Yurkovskaya

et al. 2013

Phys. Chem. Chem. Phys.

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“…In particular, it was shown that the initial longitudinal two-spin order arising from the hydrogenation reaction can be equally distributed between several spins and converted into detectable magnetization [408].…”

Section: State Of the Artmentioning

confidence: 99%

Training Schrödinger’s cat: quantum optimal control

et al. 2015

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Abstract. It is control that turns scientific knowledge into useful technology: in physics and engineering it provides a systematic way for driving a dynamical system from a given initial state into a desired target state with minimized expenditure of energy and resources. As one of the cornerstones for enabling quantum technologies, optimal quantum control keeps evolving and expanding into areas as diverse as quantumenhanced sensing, manipulation of single spins, photons, or atoms, optical spectroscopy, photochemistry, magnetic resonance (spectroscopy as well as medical imaging), quantum information processing and quantum simulation. In this communication, state-of-the-art quantum control techniques are reviewed and put into perspective by a consortium of experts in optimal control theory and applications to spectroscopy, imaging, as well as quantum dynamics of closed and open systems. We address key challenges and sketch a roadmap for future developments. ForewordThe authors of this paper represent the QUAINT consortium, a European Coordination Action on Optimal Control of Quantum Systems, funded by the European Commission Framework Programme 7, Future Emerging Technologies FET-OPEN programme and the Virtual Facility for Quantum Control (VF-QC). This consortium has considerable expertise in optimal control theory and its applications to quantum systems, both in existing areas, such as spectroscopy and imaging, and in emerging quantum technologies, such as quantum information processing, quantum communication, quantum simulation a e-mail: fwm@lusi.uni-sb.de and quantum sensing. The list of challenges for quantum control has been gathered by a broad poll of leading researchers across the communities of general and mathematical control theory, atomic, molecular-, and chemical physics, electron and nuclear magnetic resonance spectroscopy, as well as medical imaging, quantum information, communication and simulation. 144 experts in these fields have provided feedback and specific input on the state of the art, mid-term and long-term goals. Those have been summarized in this document, which can be viewed as a perspectives paper, providing a roadmap for the future development of quantum control. Because such an endeavour can hardly ever be complete (there are many additional areas of quantum control applications, such as spintronics, nano-optomechanical technologies etc.), this roadmap

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“…Specifically, the derivations of Eqs. (25) and (26), and further details of Eqs. (27) and (28) are given in the supplementary material, 42 Sec.…”

Section: F Krotov-bfgsmentioning

confidence: 99%

“…(25) and (26) is not evaluated. We note that the Hessian matrices, which initially are the N × N identity matrices, in accord with the original BFGS method also require an update,…”

Section: F Krotov-bfgsmentioning

confidence: 99%

“…15,16 Optimal control (OC) theory [17][18][19] has lately found increasing use in magnetic resonance to handle dynamic systems with a large number of controls. Recent examples include pulse sequence design in liquid- 20,21 and solid-state 22,23 NMR, hyper-polarized NMR, 24,25 and MRI. [26][27][28] In these areas, OC has demonstrated a great potential to establish experiments adapting well to technical challenges and constraints included in the cost functional, as for example, rf power limitations, 27 rf inhomogeneity, 22,23 and rf envelope "jaggedness."…”

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confidence: 99%

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Fast numerical design of spatial-selective rf pulses in MRI using Krotov and quasi-Newton based optimal control methods

Vinding

Maximov

Tošner

et al. 2012

The Journal of Chemical Physics

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A variable echo-number method for estimating R 2 in MRI-based polymer gel dosimetry Med. Phys. 38, 975 (2011) The use of increasingly strong magnetic fields in magnetic resonance imaging (MRI) improves sensitivity, susceptibility contrast, and spatial or spectral resolution for functional and localized spectroscopic imaging applications. However, along with these benefits come the challenges of increasing static field (B 0 ) and rf field (B 1 ) inhomogeneities induced by radial field susceptibility differences and poorer dielectric properties of objects in the scanner. Increasing fields also impose the need for rf irradiation at higher frequencies which may lead to elevated patient energy absorption, eventually posing a safety risk. These reasons have motivated the use of multidimensional rf pulses and parallel rf transmission, and their combination with tailoring of rf pulses for fast and low-power rf performance. For the latter application, analytical and approximate solutions are well-established in linear regimes, however, with increasing nonlinearities and constraints on the rf pulses, numerical iterative methods become attractive. Among such procedures, optimal control methods have recently demonstrated great potential. Here, we present a Krotov-based optimal control approach which as compared to earlier approaches provides very fast, monotonic convergence even without educated initial guesses. This is essential for in vivo MRI applications. The method is compared to a second-order gradient ascent method relying on the Broyden-Fletcher-Goldfarb-Shanno (BFGS) quasi-Newton method, and a hybrid scheme Krotov-BFGS is also introduced in this study. These optimal control approaches are demonstrated by the design of a 2D spatial selective rf pulse exciting the letters "JCP" in a water phantom.

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Conversion of parahydrogen induced longitudinal two-spin order to evenly distributed single spin polarisation by optimal control pulse sequences

Cited by 12 publications

References 28 publications

Manipulating spin hyper-polarization by means of adiabatic switching of a spin-locking RF-field

Manipulating spin hyper-polarization by means of adiabatic switching of a spin-locking RF-field

Training Schrödinger’s cat: quantum optimal control

Fast numerical design of spatial-selective rf pulses in MRI using Krotov and quasi-Newton based optimal control methods

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