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Teucher M, Sidabras JW, Schnegg A. Milliwatt three- and four-pulse double electron electron resonance for protein structure determination. Phys Chem Chem Phys 2022; 24:12528-12540. [PMID: 35579184 DOI: 10.1039/d1cp05508a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron paramagnetic resonance (EPR) experiments for protein structure determination using double electron-electron resonance (DEER) spectroscopy rely on high-power microwave amplifiers (>300 W) to create the short pulse lengths needed to excite a sizable portion of the spectrum. The recently introduced self-resonant microhelix combines a high B1 conversion efficiency with an intrinsically large bandwidth (low Q-value) and a high absolute sensitivity. We report dead times in 3-pulse DEER experiments as low as 14 ± 2 ns achieved using less than 1 W of power at X-band (nominally 9.5 GHz) for experiments on a molecular ruler and a T4 lysozyme sample for concentrations down to 100 μM. These low-power experiments were performed using an active volume 120 times smaller than that of a standard pulse EPR resonator, while only a 11-fold decrease in the signal-to-noise ratio was observed. Small build sizes, as realized with the microhelix, give access to volume-limited samples, while shorter dead times allow the investigation of fast relaxing spin species. With the significantly reduced dead times, the 3-pulse DEER experiment can be revisited. Here, we show experimentally that 3-pulse DEER offers superior sensitivity over 4-pulse DEER. We assert that the microhelix paves the road for low-cost benchtop X-band pulse EPR spectrometers by eliminating the need for high-power amplifiers, accelerating the adoption of pulse EPR to a broader community.
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Affiliation(s)
- Markus Teucher
- EPR Research Group, Max Planck Institute for Chemical Energy Conversion, Stift-straße 34-36, Mülheim an der Ruhr, 45470, Germany.
| | - Jason W Sidabras
- EPR Research Group, Max Planck Institute for Chemical Energy Conversion, Stift-straße 34-36, Mülheim an der Ruhr, 45470, Germany.
| | - Alexander Schnegg
- EPR Research Group, Max Planck Institute for Chemical Energy Conversion, Stift-straße 34-36, Mülheim an der Ruhr, 45470, Germany.
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2
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Probst S, Ranjan V, Ansel Q, Heeres R, Albanese B, Albertinale E, Vion D, Esteve D, Glaser SJ, Sugny D, Bertet P. Shaped pulses for transient compensation in quantum-limited electron spin resonance spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 303:42-47. [PMID: 31003062 DOI: 10.1016/j.jmr.2019.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023]
Abstract
In high sensitivity inductive electron spin resonance spectroscopy, superconducting microwave resonators with large quality factors are employed. While they enhance the sensitivity, they also distort considerably the shape of the applied rectangular microwave control pulses, which limits the degree of control over the spin ensemble. Here, we employ shaped microwave pulses compensating the signal distortion to drive the spins faster than the resonator bandwidth. This translates into a shorter echo, with enhanced signal-to-noise ratio. The shaped pulses are also useful to minimize the dead-time of our spectrometer, which allows to reduce the wait time between successive drive pulses.
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Affiliation(s)
- Sebastian Probst
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Vishal Ranjan
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Quentin Ansel
- Université de Bourgogne Franche-Comté, Laboratoire Interdisciplinaire Carnot de Bourgogne, CNRS UMR 6303, 21078 Dijon Cedex, France
| | - Reinier Heeres
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Bartolo Albanese
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Emanuele Albertinale
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Denis Vion
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Daniel Esteve
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Steffen J Glaser
- Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, D-85747 Garching, Germany; Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, D-80799 Munchen, Germany
| | - Dominique Sugny
- Université de Bourgogne Franche-Comté, Laboratoire Interdisciplinaire Carnot de Bourgogne, CNRS UMR 6303, 21078 Dijon Cedex, France
| | - Patrice Bertet
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France.
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Morton JJL, Bertet P. Storing quantum information in spins and high-sensitivity ESR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 287:128-139. [PMID: 29413326 DOI: 10.1016/j.jmr.2017.11.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/21/2017] [Accepted: 11/22/2017] [Indexed: 06/08/2023]
Abstract
Quantum information, encoded within the states of quantum systems, represents a novel and rich form of information which has inspired new types of computers and communications systems. Many diverse electron spin systems have been studied with a view to storing quantum information, including molecular radicals, point defects and impurities in inorganic systems, and quantum dots in semiconductor devices. In these systems, spin coherence times can exceed seconds, single spins can be addressed through electrical and optical methods, and new spin systems with advantageous properties continue to be identified. Spin ensembles strongly coupled to microwave resonators can, in principle, be used to store the coherent states of single microwave photons, enabling so-called microwave quantum memories. We discuss key requirements in realising such memories, including considerations for superconducting resonators whose frequency can be tuned onto resonance with the spins. Finally, progress towards microwave quantum memories and other developments in the field of superconducting quantum devices are being used to push the limits of sensitivity of inductively-detected electron spin resonance. The state-of-the-art currently stands at around 65 spins per Hz, with prospects to scale down to even fewer spins.
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Affiliation(s)
- John J L Morton
- London Centre for Nanotechnology, UCL, London WC1H 0AH, United Kingdom; Dept. of Electronic and Electrical Engineering, UCL, London WC1E 7JE, United Kingdom.
| | - Patrice Bertet
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
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4
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Doll A, Jeschke G. Wideband frequency-swept excitation in pulsed EPR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 280:46-62. [PMID: 28579102 DOI: 10.1016/j.jmr.2017.01.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 12/31/2016] [Accepted: 01/03/2017] [Indexed: 06/07/2023]
Abstract
Excitation of electron spins with monochromatic rectangular pulses is limited to bandwidths that are smaller than the spectral widths of most organic radicals and much smaller than the spectral widths of transition and rare earth metal ions. With frequency-swept pulses, bandwidths of up to 800MHz have previously been attained for excitation and detection of spin packets at frequencies of about 9.6GHz and bandwidths of up to 2.5GHz in a polarization transfer experiment at frequencies of about 34GHz. The remaining limitations, mainly due to resonator bandwidth and due to pulse length restrictions are discussed. Flip angles for state-space rotations on passage of a transition can generally be computed from the critical adiabaticity by the Landau-Zener-Stückelberg-Majorana expression. For hyperbolic secant pulses, the Demkov-Kunike model describes excitation for spin packets within and outside the sweep range. Well within the sweep range, the Bloch-Siegert phase shift is proportional to critical adiabaticity to a very good approximation. Because of the dependence of both flip angle and coherence phase on critical adiabaticity, it is advantageous to use pairs of amplitude and frequency modulation functions that provide such offset-independent adiabaticity. Compensation for the resonator response function should restore offset-independent adiabaticity. Whereas resonance offsets and Bloch-Siegert phase can be refocused at certain pulse length ratios, phase dispersion in coupled spin systems cannot generally be refocused. Based on the bandwidth limitations that arise from spin dynamics, requirements are derived for a spectrometer that achieves precise spin control over wide bands. The design of such a spectrometer and hardware characterization by EPR experiments are discussed.
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Affiliation(s)
- Andrin Doll
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Gunnar Jeschke
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland.
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Spindler PE, Schöps P, Kallies W, Glaser SJ, Prisner TF. Perspectives of shaped pulses for EPR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 280:30-45. [PMID: 28579101 DOI: 10.1016/j.jmr.2017.02.023] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 02/27/2017] [Accepted: 02/28/2017] [Indexed: 06/07/2023]
Abstract
This article describes current uses of shaped pulses, generated by an arbitrary waveform generator, in the field of EPR spectroscopy. We show applications of sech/tanh and WURST pulses to dipolar spectroscopy, including new pulse schemes and procedures, and discuss the more general concept of optimum-control-based pulses for applications in EPR spectroscopy. The article also describes a procedure to correct for experimental imperfections, mostly introduced by the microwave resonator, and discusses further potential applications and limitations of such pulses.
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Affiliation(s)
- Philipp E Spindler
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Germany
| | - Philipp Schöps
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Germany
| | - Wolfgang Kallies
- Department of Chemistry, Technical University of Munich, Germany
| | - Steffen J Glaser
- Department of Chemistry, Technical University of Munich, Germany
| | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Germany.
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6
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Park DK, Feng G, Rahimi R, Baugh J, Laflamme R. Randomized benchmarking of quantum gates implemented by electron spin resonance. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 267:68-78. [PMID: 27131777 DOI: 10.1016/j.jmr.2016.04.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 04/18/2016] [Accepted: 04/20/2016] [Indexed: 06/05/2023]
Abstract
Spin systems controlled and probed by magnetic resonance have been valuable for testing the ideas of quantum control and quantum error correction. This paper introduces an X-band pulsed electron spin resonance spectrometer designed for high-fidelity coherent control of electron spins, including a loop-gap resonator for sub-millimeter sized samples with a control bandwidth ∼40MHz. Universal control is achieved by a single-sideband upconversion technique with an I-Q modulator and a 1.2GS/s arbitrary waveform generator. A single qubit randomized benchmarking protocol quantifies the average errors of Clifford gates implemented by simple Gaussian pulses, using a sample of gamma-irradiated quartz. Improvements in unitary gate fidelity are achieved through phase transient correction and hardware optimization. A preparation pulse sequence that selects spin packets in a narrowed distribution of static fields confirms that inhomogeneous dephasing (1/T2(∗)) is the dominant source of gate error. The best average fidelity over the Clifford gates obtained here is 99.2%, which serves as a benchmark to compare with other technologies.
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Affiliation(s)
- Daniel K Park
- Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada; Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Guanru Feng
- Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada; Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Robabeh Rahimi
- Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada; Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Jonathan Baugh
- Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada; Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada; Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
| | - Raymond Laflamme
- Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada; Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada; Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2J 2W9, Canada; Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
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Pribitzer S, Doll A, Jeschke G. SPIDYAN, a MATLAB library for simulating pulse EPR experiments with arbitrary waveform excitation. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 263:45-54. [PMID: 26773526 DOI: 10.1016/j.jmr.2015.12.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 12/22/2015] [Accepted: 12/23/2015] [Indexed: 06/05/2023]
Abstract
Frequency-swept chirp pulses, created with arbitrary waveform generators (AWGs), can achieve inversion over a range of several hundreds of MHz. Such passage pulses provide defined flip angles and increase sensitivity. The fact that spectra are not excited at once, but single transitions are passed one after another, can cause new effects in established pulse EPR sequences. We developed a MATLAB library for simulation of pulse EPR, which is especially suited for modeling spin dynamics in ultra-wideband (UWB) EPR experiments, but can also be used for other experiments and NMR. At present the command line controlled SPin DYnamics ANalysis (SPIDYAN) package supports one-spin and two-spin systems with arbitrary spin quantum numbers. By providing the program with appropriate spin operators and Hamiltonian matrices any spin system is accessible, with limits set only by available memory and computation time. Any pulse sequence using rectangular and linearly or variable-rate frequency-swept chirp pulses, including phase cycling can be quickly created. To keep track of spin evolution the user can choose from a vast variety of detection operators, including transition selective operators. If relaxation effects can be neglected, the program solves the Liouville-von Neumann equation and propagates spin density matrices. In the other cases SPIDYAN uses the quantum mechanical master equation and Liouvillians for propagation. In order to consider the resonator response function, which on the scale of UWB excitation limits bandwidth, the program includes a simple RLC circuit model. Another subroutine can compute waveforms that, for a given resonator, maintain a constant critical adiabaticity factor over the excitation band. Computational efficiency is enhanced by precomputing propagator lookup tables for the whole set of AWG output levels. The features of the software library are discussed and demonstrated with spin-echo and population transfer simulations.
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Affiliation(s)
- Stephan Pribitzer
- ETH Zurich, Lab. Phys. Chem., Vladimir-Prelog Weg 2, 8093 Zurich, Switzerland
| | - Andrin Doll
- ETH Zurich, Lab. Phys. Chem., Vladimir-Prelog Weg 2, 8093 Zurich, Switzerland
| | - Gunnar Jeschke
- ETH Zurich, Lab. Phys. Chem., Vladimir-Prelog Weg 2, 8093 Zurich, Switzerland
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