Quantum simulation of spin ordering with nuclear spins in a solid-state lattice

Roumpos, Georgios; Master, Cyrus P.; Yamamoto, Yoshihisa

doi:10.1103/physrevb.75.094415

Cited by 18 publications

(16 citation statements)

References 35 publications

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“…The pulse tech-niques are often utilized for quantum simulation experiments. For example, Ising type Hamiltonian X i X j can be changed to X i X j +Y i Y j +aZ i Z j for any parameters a, with applying the multiple pulse sequence with a parameter for spacing between pulses, a [33]. It was shown in a quantum simulation experiment [34] that the dynamical behavior of a nuclear spin system with the interactions X i X j + (2a − 1)Y i Y j − 2aZ i Z j are substantially different depending on a.…”

Section: Discussionmentioning

confidence: 99%

Boosting Computational Power through Spatial Multiplexing in Quantum Reservoir Computing

et al. 2019

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Quantum reservoir computing provides a framework for exploiting the natural dynamics of quantum systems as a computational resource. It can implement real-time signal processing and solve temporal machine learning problems in general, which requires memory and nonlinear mapping of the recent input stream using the quantum dynamics in computational supremacy region, where the classical simulation of the system is intractable. A nuclear magnetic resonance spin-ensemble system is one of the realistic candidates for such physical implementations, which is currently available in laboratories. In this paper, considering these realistic experimental constraints for implementing the framework, we introduce a scheme, which we call a spatial multiplexing technique, to effectively boost the computational power of the platform. This technique exploits disjoint dynamics, which originate from multiple different quantum systems driven by common input streams in parallel. Accordingly, unlike designing a single large quantum system to increase the number of qubits for computational nodes, it is possible to prepare a huge number of qubits from multiple but small quantum systems, which are operationally easy to handle in laboratory experiments. We numerically demonstrate the effectiveness of the technique using several benchmark tasks and quantitatively investigate its specifications, range of validity, and limitations in detail.

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Section: Discussionmentioning

confidence: 99%

Boosting Computational Power through Spatial Multiplexing in Quantum Reservoir Computing

et al. 2019

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“…In ) the emulation of the dynamics of single spins with principal quantum number s = 1/2, 1 and 3/2 was demonstrated (see Figure 18). The antiferromagnetic Heisenberg model with long-range interactions could be realized with solidstate NMR (Roumpos et al, 2007). Itinerant ferromagnetism could be studied in a two-component Fermi gas (Jo et al, 2009).…”

Section: Spin Modelsmentioning

confidence: 99%

Quantum simulation

2014

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Simulating quantum mechanics is known to be a difficult computational problem, especially when dealing with large systems. However, this difficulty may be overcome by using some controllable quantum system to study another less controllable or accessible quantum system, i.e., quantum simulation. Quantum simulation promises to have applications in the study of many problems in, e.g., condensed-matter physics, high-energy physics, atomic physics, quantum chemistry and cosmology. Quantum simulation could be implemented using quantum computers, but also with simpler, analog devices that would require less control, and therefore, would be easier to construct. A number of quantum systems such as neutral atoms, ions, polar molecules, electrons in semiconductors, superconducting circuits, nuclear spins and photons have been proposed as quantum simulators. This review outlines the main theoretical and experimental aspects of quantum simulation and emphasizes some of the challenges and promises of this fast-growing field.

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“…Bulk nuclear hyperpolarization in such low magnetic fields is desirable for scattering experiments with unstable nuclei, neutrons, and elementary particles (3,33). The low entropic state of a bulk nuclear spin ensemble can be used for quantum information processing experiments: quantum sensing toward single nuclear spin detection (34)(35)(36), quantum computing (37), and studies on magnetic phase transition, which is presently a hot topic in quantum simulation (38,39) In conclusion, by using electron spins in photo-excited triplet states, we can acquire a higher DNP enhancement factor than the conventional limit, 660, using electron spins in thermal equilibrium, while maintaining a bulk sample at room temperature. By deuteration of the polarizing agent and regioselective deuteration of the host, we have achieved the 1 H spin polarization of 34%.…”

Section: Significancementioning

confidence: 99%

Room temperature hyperpolarization of nuclear spins in bulk

Tateishi

Negoro

Nishida

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

128

161

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Dynamic nuclear polarization (DNP), a means of transferring spin polarization from electrons to nuclei, can enhance the nuclear spin polarization (hence the NMR sensitivity) in bulk materials at most 660 times for 1 H spins, using electron spins in thermal equilibrium as polarizing agents. By using electron spins in photo-excited triplet states instead, DNP can overcome the above limit. We demonstrate a 1 H spin polarization of 34%, which gives an enhancement factor of 250,000 in 0.40 T, while maintaining a bulk sample (∼0.6 mg, ∼0.7 × 0.7 × 1 mm 3 ) containing >10 19 1 H spins at room temperature. Room temperature hyperpolarization achieved with DNP using photo-excited triplet electrons has potentials to be applied to a wide range of fields, including NMR spectroscopy and MRI as well as fundamental physics.N uclear spin is a useful probe for noninvasive analysis of bulk materials such as chemical compounds, industrial products, biological samples, and human bodies. The signal from a spin ensemble is proportional to the polarization P. In thermal equilibrium in a magnetic field B at temperature T, P for spin-1/2 particles is given bywhere Z is the Planck constant, k is the Boltzmann constant, and γ is the gyromagnetic ratio. In a magnetic field of several teslas at room temperature, the nuclear spin energy ZγB=2 is much smaller than the thermal energy kT, so nuclear spins are only slightly polarized. This is the major reason why the sensitivity of NMR spectroscopy and MRI is so low. Dynamic nuclear polarization (DNP) is a means of transferring spin polarization from electrons to nuclei. As a method to enhance the bulk nuclear polarization, DNP has been successfully applied to areas ranging from fundamental physics (1-3) to materials science (4), biology (5-7), and medical science (8), since it was discovered 60 y ago (9, 10). As long as electron spins in thermal equilibrium are used as polarizing agents, the upper limit of the polarization enhancement is 660 for 1 H spins and cryogenic temperatures of around 4.2 K are required for hyperpolarization in the order of 10% even in the strong magnetic fields used for NMR. Hyperpolarization at room temperature will simplify instrumentation and expand the sample variety to materials that prefer ambient temperatures. Other techniques such as optical pumping in semiconductors (11) and the Haupt effect (12) also require cryogenic temperature for increasing bulk polarization beyond 10%.One solution for overcoming the upper limit of the enhancement factor of the conventional DNP, γ e =γ n , is to use nonthermalized electron spins as polarizing agents. A number of organic molecules have photo-excited triplet states where, due to the selection rule in the intersystem crossing from the excited singlet state to the triplet state, the population distribution is highly biased. DNP using electron spins in the photo-excited triplet state can achieve hyperpolarization independent of the magnetic field strength and temperature (13)(14)(15)(16). In this work, we have achieved a bulk hy...

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Quantum simulation of spin ordering with nuclear spins in a solid-state lattice

Cited by 18 publications

References 35 publications

Boosting Computational Power through Spatial Multiplexing in Quantum Reservoir Computing

Boosting Computational Power through Spatial Multiplexing in Quantum Reservoir Computing

Quantum simulation

Room temperature hyperpolarization of nuclear spins in bulk

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