A solution with hyperpolarized nuclear spins encoded into a long-lived state has been utilized for sensing chemical phenomena. In a conventional way, nuclear spins are hyperpolarized at very low temperatures. In this work, we demonstrate the encoding of a four-nuclear-spin system hyperpolarized at room temperature into a long-lived state in a solution. We apply the solution with the long-lived state as a sensor in ligand--receptor binding experiments.
The nuclear spin singlet order involving coupled pairs of spins-1/2 may be used to store nuclear spin hyperpolarization in a room temperature liquid for a time much longer than the spin-lattice relaxation time $T_1$. There both are observations of long-lived homonuclear and heteronuclear spin-singlet order. Although hyperpolarized singlet order of the same species are accessible, hyperpolarized heteronuclear spin-singlet order has not been presented yet. Here we show hyperpolarized singlet order is achievable in the sample of $^{13}$C-labeled formic acid solution at room temperature by using o…
The use of hyperpolarized agents in magnetic resonance (MR), such as 13C-labeled compounds, enables powerful new imaging and detection modalities that stem from a 10,000-fold boost in signal. A major challenge for the future of the hyperpolarizaton technique is the inherently short spin relaxation times, typically < 60 seconds for 13C liquid-state compounds, which limit the time that the signal remains boosted. Here, we demonstrate that 1.1% natural abundance 13C spins in synthetic nanodiamond (ND) can be hyperpolarized at cryogenic and room temperature without the use of toxic free- radicals,…
We report the observation of long-lived Floquet prethermal states in a bulk solid composed of dipolar-coupled $^{13}$C nuclei in diamond at room temperature. For precessing nuclear spins prepared in an initial transverse state, we demonstrate pulsed spin-lock Floquet control that prevents their decay over multiple-minute long periods. We observe Floquet prethermal lifetimes $T_2'\approx$90.9s, extended >60,000-fold over the nuclear free induction decay times. The spins themselves are continuously interrogated for $\sim$10min, corresponding to the application of $\approx$5.8M control pulses. Th…
Dynamic Nuclear Polarization (DNP) is a powerful suite of techniques that deliver multifold signal enhancements in NMR and MRI. The generated athermal spin states can also be exploited for quantum sensing and as probes for many-body physics. Typical DNP methods require use of cryogens, large magnetic fields, and high power microwaves, which are expensive and unwieldy. Nanodiamond particles, rich in Nitrogen-Vacancy (NV) centers, have attracted attention as alternative DNP agents because they can potentially be optically hyperpolarized at room temperature. Indeed the realization of a miniature …
Methods that preserve coherence broadly impact all quantum information processing and metrology applications. Dynamical decoupling methods accomplish this by protecting qubits in noisy environments but are typically constrained to the limit where the qubits themselves are non-interacting. Here we consider the alternate regime wherein the inter-qubit couplings are of the same order as dephasing interactions with the environment. We propose and demonstrate a multi-pulse protocol that protects transverse spin states by suitably Hamiltonian engineering the inter-spin coupling while simultaneously …
The coherent high-fidelity generation of nuclear spins in long-lived singlet states which may find application as quantum memory or sensor represents a considerable experimental challenge. Here we propose a dissipative scheme that achieves the preparation of pairs of nuclear spins in long-lived singlet states by a protocol that combines the interaction between the nuclei and a periodically reset electron spin of an NV center with local rf-control of the nuclear spins. The final state of this protocol is independent of the initial preparation of the nuclei, is robust to external field fluctuati…
Heralded single-photon sources with on-demand readout are promising candidates for quantum repeaters enabling long-distance quantum communication. The need for scalability of such systems requires simple experimental solutions, thus favouring room-temperature systems. For quantum repeater applications, long delays between heralding and single-photon readout are crucial. Until now, this has been prevented in room-temperature atomic systems by fast decoherence due to thermal motion. Here we demonstrate efficient heralding and readout of single collective excitations created in warm caesium vapou…
Circular Rydberg states are ideal tools for quantum technologies, with huge mutual interactions and extremely long lifetimes in the tens of milliseconds range, two orders of magnitude larger than those of laser-accessible Rydberg states. However, such lifetimes are observed only at zero temperature. At room temperature, blackbody-radiation-induced transfers annihilate this essential asset of circular states, which have thus been used mostly so far in specific, complex cryogenic experiments. We demonstrate here, on a laser-cooled atomic sample, a circular state lifetime of more than one millise…
Light storage, the controlled and reversible mapping of photons onto long-lived states of matter [1], enables memory capability in optical quantum networks [2-6]. Prominent storage media are warm alkali gases due to their strong optical coupling and long-lived spin states [7,8]. In a dense gas, the random atomic collisions dominate the lifetime of the spin coherence, limiting the storage time to a few milliseconds [9,10]. Here we present and experimentally demonstrate a storage scheme that is insensitive to spin-exchange collisions, thus enabling long storage times at high atomic densities. Th…
Dynamic nuclear polarization via contact with electronic spins has emerged as an attractive route to enhance the sensitivity of nuclear magnetic resonance (NMR) beyond the traditional limits imposed by magnetic field strength and temperature. Among the various alternative implementations, the use of nitrogen vacancy (NV) centers in diamond - a paramagnetic point defect whose spin can be optically polarized at room temperature - has attracted widespread attention, but applications have been hampered by the need to align the NV axis with the external magnetic field. Here we overcome this hurdle …
A method to generate long-lived isomeric states effectively for Mossbauer applications is reported. We demonstrate that this method is better and easier to provide highly sensitive Mossbauer effect of long-lived isomers (>1ms) such as 103Rh. Excitation of (gamma,gamma) process by synchrotron radiation is painful due mainly to their limited linewidth. Instead,(gamma,gamma') process of bremsstrahlung excitation is applied to create these long-lived isomers. Isomers of 45Sc, 107Ag, 109Ag, and 103Rh have been generated from this method. Among them, 103Rh is the only one that we have obtained the g…
We demonstrate optically pumped dynamic nuclear polarization of 29-Si nuclear spins that are strongly coupled to paramagnetic color centers in 4H- and 6H-SiC. The 99 +/- 1% degree of polarization at room temperature corresponds to an effective nuclear temperature of 5 microKelvin. By combining ab initio theory with the experimental identification of the color centers' optically excited states, we quantitatively model how the polarization derives from hyperfine-mediated level anticrossings. These results lay a foundation for SiC-based quantum memories, nuclear gyroscopes, and hyperpolarized pro…
Nuclear spins of noble-gas atoms are exceptionally isolated from the environment and can maintain their quantum properties for hours at room temperature. Here we develop a mechanism for entangling two such distant macroscopic ensembles by using coherent light input. The interaction between the light and the noble-gas spins in each ensemble is mediated by spin-exchange collisions with alkali-metal spins, which are only virtually excited. The relevant conditions for experimental realizations with ^{3}\text{He} or ^{129}\text{Xe} are outlined.
Nuclear spins support long lived quantum coherence due to weak coupling to the environment, but are difficult to rapidly control using nuclear magnetic resonance (NMR) as a result of the small nuclear magnetic moment. We demonstrate a fast ~ 500 ns nuclear spin phase gate on a 14N nuclear spin qubit intrinsic to a nitrogen-vacancy (NV) center in diamond. The phase gate is enabled by the hyperfine interaction and off-resonance driving of electron spin transitions. Repeated applications of the phase gate bang-bang decouple the nuclear spin from the environment, locking the spin state for up to ~…
The physical basis for observed long-lived electronic coherence in photosynthetic light-harvesting systems is identified using an analytically soluble model. Three physical features are found to be responsible for their long coherence lifetimes: i) the small energy gap between excitonic states, ii) the small ratio of the energy gap to the coupling between excitonic states, and iii) the fact that the molecular characteristics place the system in an effective low temperature regime, even at ambient conditions. Using this approach, we obtain decoherence times for a dimer model with FMO parameters…
We report experimental observations of the long-lived rhodium Mossbauer emissions by the time- and energy-resolved spectroscopy. The extraordinary observations manifest the open-up of photonic band gap in analogy to the superconducting gap of remarkable symmetry breakings at transition point. These observations are of potential importance for detecting gravitational waves and development of the two-photon gamma laser. Firstly, phase transitions shown by spectral evolution of characteristic emissions reveal the different aggregate exciton orderings at room temperature. Six different phases are …
We use nominally forbidden electron-nuclear spin transitions in nitrogen-vacancy (NV) centers in diamond to demonstrate coherent manipulation of a nuclear spin ensemble using microwave fields at room temperature. We show that employing an off-axis magnetic field with a modest amplitude($\approx$ 0.01 T) at an angle with respect to the NV natural quantization axes is enough to tilt the direction of the electronic spins, and enable efficient spin exchange with the nitrogen nuclei of the NV center. We could then demonstrate fast Rabi oscillations on electron-nuclear spin exchanging transitions, c…
Here we propose and analyse in detail protocols that can achieve rapid hyperpolarization of 13C nuclear spins in randomly oriented ensembles of nanodiamonds at room temperature. Our protocols exploit a combination of optical polarization of electron spins in nitrogen-vacancy centers and the transfer of this polarization to 13C nuclei by means of microwave control to overcome the severe challenges that are posed by the random orientation of the nanodiamonds and their nitrogen-vacancy centers. Specifically, these random orientations result in exceedingly large energy variations of the electron s…
Photosynthetic antenna complexes capture and concentrate solar radiation by transferring the excitation to the reaction center which stores energy from the photon in chemical bonds. This process occurs with near-perfect quantum efficiency. Recent experiments at cryogenic temperatures have revealed that coherent energy transfer - a wavelike transfer mechanism - occurs in many photosynthetic pigment-protein complexes (1-4). Using the Fenna-Matthews-Olson antenna complex (FMO) as a model system, theoretical studies incorporating both incoherent and coherent transfer as well as thermal dephasing p…
Scalable and telecom single-erbium system with record-long room-temperature quantum coherence
College of Nanotechnology, Science, and Engineering (CNSE), Department of Nanoscale Science and Engineering, University at Albany (UAlbany)（奥尔巴尼大学纳米技术、科学与工程学院）
The exquisite properties of Rydberg levels make them particularly appealing for emerging quantum technologies. The lifetime of low-angular-momentum laser-accessible levels is however limited to a few $100\,μ\mathrm{s}$ by optical transitions and microwave blackbody radiation (BBR) induced transfers at room temperature. A considerable improvement would be obtained with the few $10\,\mathrm{ms}$ lifetime of circular Rydberg levels in a cryogenic environment reducing the BBR temperature. We demonstrate the preparation of long-lived circular Rydberg levels of laser-cooled Rubidium atoms in a cryos…
Long-lived electronic coherences in various photosynthetic complexes at cryogenic and room temperature have generated vigorous efforts both in theory and experiment to understand their origins and explore their potential role to biological function. The ultrafast signals resulting from the experiments that show evidence for these coherences result from many contributions to the molecular polarization. Quantum process tomography (QPT) was conceived in the context of quantum information processing to characterize and understand general quantum evolution of controllable quantum systems, for examp…
Three-dimensional arrays of silicon transistors increase the density of bits. Solid-state qubits are much larger so could benefit even more from using the third dimension given that useful fault-tolerant quantum computing will require at least 100,000 physical qubits and perhaps one billion. Here we use laser writing to create 3D arrays of nitrogen-vacancy centre (NVC) qubits in diamond. This would allow 5 million qubits inside a commercially available 4.5x4.5x0.5 mm diamond based on five nuclear qubits per NVC and allowing $(10 μm)^3$ per NVC to leave room for our laser-written electrical con…
Quantum interfaces between photons and ensembles of atoms have emerged as powerful tools for quantum technologies. A major objective for such interfaces is high fidelity storage and retrieval of a photon in a collective quantum state of many atoms. This requires long-lived collective superposition states, which is typically achieved with immobilized atoms. Thermal atomic vapors, which present a simple and scalable resource, have, so far, only been used for continuous variable processing or for discrete variable processing on short time scales where atomic motion is negligible. We develop a the…
The Posner molecule, $\text{Ca}_9(\text{PO}_4)_6$, has long been recognized to have biochemical relevance in various physiological processes. It has found recent attention for its possible role as a biological quantum information processor, whereby the molecule purportedly maintains long-lived nuclear spin coherences among its ${^{31}\text{P}}$ nuclei (presumed to be symmetrically arranged), allowing it to function as a room temperature qubit. The structure of the molecule has been of much dispute in the literature, although the $\text{S}_6$ point group symmetry has often been assumed and expl…
Parahydrogen Cooling of Nuclear Spin Chains at Hypogeomagnetic Fields
International Tomography Center, SB RAS（俄罗斯科学院西伯利亚分院国际成像中心）；Novosibirsk State University（新西伯利亚国立大学）；Chimie Physique et Chimie du Vivant (CPCV, UMR 8228), Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université（巴黎高等师范学院化学系物理与生命化学实验室（CPCV，UMR 8228），PSL大学，索邦大学）；Johannes Gutenberg University, Institute of Physics（约翰内斯·古腾堡大学物理研究所）；Helmholtz Institute Mainz（美因茨亥姆霍兹研究所）；GSI Helmholtzzentrum für Schwerionenforschung GmbH（德国重离子研究中心亥姆霍兹有限公司）；Department of Chemistry, University of Miami（迈阿密大学化学系）；Department of Physics, University of Miami（迈阿密大学物理系）；Frost Institute for Chemistry and Molecular Science（弗罗斯特化学与分子科学研究所）
Nuclear spins of noble gases feature extremely long coherence times but are inaccessible to optical photons. Here we realize a coherent interface between light and noble-gas spins that is mediated by alkali atoms. We demonstrate the optical excitation of the noble-gas spins and observe the coherent back-action on the light in the form of high-contrast two-photon spectra. We report on a record two-photon linewidth of 5$\pm$0.7 mHz (millihertz) above room-temperature, corresponding to a one-minute coherence time. This experiment provides a demonstration of coherent bi-directional coupling betwee…
Nuclear spins in solids exhibit long coherence times due to the small nuclear gyromagnetic ratio. This weak environmental coupling comes at the expense of slow quantum gate operations, which should be as fast as possible for many applications in quantum information processing and sensing. In this work, we use nitrogen-vacancy (NV) centers in diamond to probe the nuclear spins within dark paramagnetic nitrogen defects (P1 centers) in the diamond lattice. The gyromagnetic ratio of the P1 nuclear spin is augmented by hyperfine coupling to the electron spin, resulting in greatly enhanced coupling …
Newly discovered van der Waals materials like MoS$_2$, WSe$_2$, hexagonal boron nitride (h-BN), and recently $\mathrm{C}_2\mathrm{N}$ have sparked intensive research to unveil the quantum behavior associated with their 2D structure. Of great interest are 2D materials that host single quantum emitters. h-BN, with a band gap of 5.95 eV, has been shown to host single quantum emitters which are stable at room temperature in the UV and visible spectral range. In this paper we investigate correlations between h-BN structural features and emitter location from bulk down to the monolayer at room tempe…
Photosynthetic antenna complexes are responsible for absorbing energy from sunlight and transmitting it to remote locations where it can be stored. Recent experiments have found that this process involves long-lived quantum coherence between pigment molecules, called chromophores, which make up these complexes. Expected to decay within 100 fs at room temperature, these coherences were instead found to persist for picosecond time scales, despite having no apparent isolation from the thermal environment of the cell. This paper derives a quantum master equation which describes the coherent evolut…
Quantum-Driven Neuromorphic Computing for Million-Qubit-Scale Workloads
Dynex Holding Establishment；Surrey Institute for People-Centred Artificial Intelligence, Faculty of Engineering and Physical Sciences, University of Surrey（萨里大学工程与物理科学学院以人为本的人工智能研究所）
We propose to take advantage of the weak coupling of ground-state helium-3 nuclear spin to its environment to produce long-lived macroscopic quantum states, nuclear spin squeezed states, in a gas cell at room temperature. To perform a quantum non-demolition measurement of a transverse component of the polarized collective nuclear spin, we maintain a population in helium-3 metastable state with a discharge. The collective spin associated to $F=1/2$ metastable level hybridizes with the ground state one by metastability exchange collisions. To access nuclear spin fluctuations, one continuously me…
