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Review of noble-gas spin amplification via the spin-exchange collisions

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Science China(Information Sciences) 2022年第10期65卷 5-23页

作者： Haowen SU Min JIANG xinhua peng CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences University of Science and Technology of China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China

Due to isolation from the environment with the protection of the full electronic shells, nuclear spins of noble gas typically feature extraordinary long coherence times, high polarization and good chemical inertness, which makes themselves attractive in extensive scientific applications. Recently, the noble-gas spin amplification via the spin-exchange collisions between overlapping noble-gas spins and alkali-atom spins has been theoretically and experimentally demonstrated in various quantum techniques including maser, Floquet maser, spin-based amplifier, and Floquet spin amplifier. The noble-gas spin amplification can enhance the external oscillating magnetic field by a factor of more than 100 and realize ultrasensitive magnetometry,which is important for the detection of weak electromagnetic fields and hypothetical particles. Based on the spin amplification, experiments have been conducted to search for axion-like dark matter and exotic spindependent forces and new constraints have been established. This review summarizes the recent progress on noble-gas spin amplification, including the basic principles, methods, different types, the related applications ranging from magnetic-field sensing to searches for new physics, and prospects for further improvements.

关键词： nuclear spin noble gas maser spin amplification Floquet system

Hydrologic separation and their contributions to N loss in an agricultural catchment in hilly red soil region

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Science China Earth Sciences 2019年第11期62卷 1730-1743页

作者： Yaji WANG Lei GAO xinhua peng State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Beijing 100081China

The impacts of hydrological processes on N loss is of great value to understand the N transport at catchment scale,which is far from clear. Rainfall, soil water, groundwater and stream water and their N concentrations were monitored from March 2017 to February 2018 in Sunjia agricultural catchment of the red soil critical zone. Objectives of this study were:(1) to determine the dynamics of N concentration of different waters and their N loads;(2) to assess their contributions to N load of streamflow in the paddy and upland mixed agricultural catchment. Our results showed that the N concentrations of soil water(4.8 mg L^(-1)) and groundwater(6.0 mg L^(-1)) were the highest, approximately 2 to 5 times higher than those of stream water(2.7 mg L^(-1)), rain water(1.7 mg L^(-1)) and irrigation water(1.2 mg L^(-1)). The N net loss of the catchment(38.2 kg ha^(-1) yr^(-1))accounted for 15% of the total fertilizer N input. Rainy season(April–June) was a high-risk period of N loss, contributing to more than one third of the total annual loss amount. Using end-member mixing analysis model(EMMA), we found groundwater(whose discharge accounted for 25% of the catchment streamflow) was an important source for the N loss in the agricultural catchment. Even in this catchment with coexisting upland and paddy field ecosystems, identified end-members could be used to predict the N load well(R^2>0.87, p<0.001). These results can deepen our understanding of the relationship between hydrological process and N transport in the red soil critical zone and are also helpful to improve the water and fertilizer management in subtropical agricultural catchment.

关键词： End-member mixing analysis model Hydrological separation Groundwater N load Red soil critical zone

Algorithmic cooling based on cross-relaxation and decoherence-free subspace

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Science China(Physics,Mechanics & Astronomy) 2020年第7期63卷 47-57页

作者： Heng Yan Wang Jian Pan Wen Qiang Zheng xinhua peng Department of Physics Zhejiang University of Science and TechnologyHangzhou 310023China Hefei National Laboratory for Physical Sciences at the Microscale Department of Modern PhysicsUniversity of Science and Technology of ChinaHefei 230026China CAS Key Laboratory of Microscale Magnetic Resonance University of Science and Technology of ChinaHefei 230026China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China Collaborative Innovation Center for Bio-Med Physics Information Technology College of ScienceZhejiang University of TechnologyHangzhou 310023China

Heat-bath algorithmic cooling(HBAC)has been proven to be a powerful and effective method for obtaining high polarization of the target *** cooling upper bound has been recently found using a specific algorithm,the partner pairing algorithm(PPAHBAC).It has been shown that by including cross-relaxation,it is possible to surpass the cooling ***,by combining cross-relaxation and decoherence-free subspace,we present a two-qubit reset sequence and then generate a new algorithmic cooling(AC)technique using irreversible polarization compression to further surpass the *** proposed two-qubit reset sequence can prepare one of the two qubits to four times the polarization of a single-qubit reset operation in PPA-HBAC for low *** the qubit number is large,the cooling limit of the proposed AC is approximately five times as high as the *** results reveal that cross-relaxation and decoherence-free subspace are promising resources to create new AC for higher polarization.

关键词： algorithmic cooling polarization enhancing cross-relaxation decoherence-free subspace

Feedback control for manipulating magnetization in spin-exchange optical pumping system

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Science China(Physics,Mechanics & Astronomy) 2018年第8期61卷 27-32页

作者： Ke Zhang Jun Li Min Jiang Nan Zhao xinhua peng Beijing Computational Science Research Center Bejing 100193Chin Hefei National Laboratory for Physical Sciences at Microscale Department of Modern PhysicsUniversity of Science and Technology of ChinaHefei 230026China Synergetic Innovation Center of Quantum Information&Quantum Physics University of Science and Technology of ChinaHefei 230026China

Control of magnetization plays an important role in the scientific and technological field of manipulating spin systems. In this work, we study the problem of manipulating nuclear magnetization in the spin-exchange optical pumping system, including accelerating the recovery of nuclear polarization and fixing it on a specific desired state. A real-time feedback control strategy is exploited here. We have also done some numerical simulations, with the results clearly demonstrating the effectiveness of our method, that the nuclear magnetization is able to be driven towards the equilibrium state at a much faster speed and also can be stabilized to a target state. We expect that our feedback control method can find applications in gyro experiments.

关键词： optical pumping feedback control nuclear magnetic resonance state stabilization

Pore shrinkage capacity of Shajiang black soils(Vertisols)on the North China Plain and its influencing factors

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Pedosphere 2024年第3期34卷 620-630页

作者： Yueming CHEN Zhongbin ZHANG Lei GAO Zichun GUO peng XIONG Fahui JIANG xinhua peng State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008(China) University of Chinese Academy of Sciences Beijing 100049(China) Jiangxi Agricultural University Nanchang 330045(China)

Different pore sizes present different pore shrinkage capacities in a nonrigid ***,the shrinkage capacities of different pore sizes and their influencing factors are not *** aimed to quantify the shrinkage capacities of different pore sizes(large pores,>50μm;medium pores,0.2-50μm;fine pores,<0.2μm)and determine how soil properties impact soil shrinkage capacity at the regional *** sampling transects from west to east(360 km long,35 samples)and from north to south(190 km long,29 samples)were selected to investigate soil shrinkage capacity and physicochemical properties of at0-20 cm depth in the Vertisol(locally known as Shajiang black soil)region of the North China *** results showed that soil total shrinkage capacity,indicated by the coefficient of linear extensibility(COLE),had a mean value of 0.041-0.051 in the west-east and north-south *** pores had higher pore shrinkage index(PSI)values(0.103-0.109)than medium(0.077-0.096)and fine(0.087-0.091)*** PSI of fine pores showed a fluctuating increasing trend from northwest to southeast,and the fine pore shrinkage capacity determined the COLE(r^(2)=0.789,P<0.001).The PSI of large pores had a significant relationship with soil bulk density(r=0.281,P<0.05)and organic carbon(r=-0.311,P<0.05),whereas those of medium and fine pores were correlated with soil clay content(r=0.381 and 0.687,respectively,P<0.001).In addition,the PSI of fine pores was also correlated with montmorillonite content(r=0.387,P<0.01).It can be concluded that the PSI of large pores is related to anthropogenically influenced soil properties with low stability,whereas those of medium and fine pores are related to pedogenic *** high variability in anthropogenic and pedogenic factors explains the spatial pattern of Vertisol shrinkage capacity on the North China Plain.

关键词： clay content coefficient of linear extensibility pore shrinkage index soil structure spatial distribution swelling

Generic preparation and entanglement detection of equal superposition states

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Science China(Physics,Mechanics & Astronomy) 2017年第7期60卷 32-39页

作者： Qi Yu YanBao Zhang Jun Li HengYan Wang xinhua peng JiangFeng Du Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics University of Science and Technology of China Hefei 230026 China Institute for Quantum Computing and Department of Physics and Astronomy University of Waterloo Waterloo N2L 3G1 Canada Beijing Computational Science Research Center Beijing 100084 China Synergetic Innovation Center of Quantum Information & Quantum Physics University of Science and Technology of China Hefei 230026 China College of Physics and Electronic Science Hubei Normal University Huangshi 435002 China

Quantum superposition is a fundamental principle of quantum mechanics, so it is not surprising that equal superposition states(ESS) serve as powerful resources for quantum information processing. In this work, we propose a quantum circuit that creates an arbitrary dimensional ESS. The circuit construction is efficient as the number of required elementary gates scales polynomially with the number of required qubits. For experimental realization of the method, we use techniques of nuclear magnetic resonance(NMR). We have succeeded in preparing a 9-dimensional ESS on a 4-qubit NMR quantum register. The full tomography indicates that the fidelity of our prepared state with respect to the ideal 9-dimensional ESS is over 96%. We also prove the prepared state is pseudo-entangled by directly measuring an entanglement witness operator. Our result can be useful for the implementation of those quantum algorithms that require an ESS as an input state.

关键词： equal superposition states nuclear magnetic resonance quantum algorithms quantum entanglement

On the use of cross polarization in solid-state NMR:1 H spinlock versus adiabatic demagnetization in the rotating frame

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Magnetic Resonance Letters 2022年第3期2卷 147-158页

作者： Yuchen Li Shengyu Zhang Ze Wu xinhua peng Riqiang Fu CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences University of Science and Technology of ChinaHefei230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei230026China Hefei National Laboratory Hefei230088China National High Magnetic Field Laboratory 1800 East Paul Dirac DriveTallahasseeFL32310USA

Cross polarization(CP)is a widely used solid-state nuclear magnetic resonance(NMR)technique for enhancing the polarization of dilute S spins from much larger polarization of abundant I spins such as 1 *** achieve such a polarization transfer,the I spin should either be spin-locked or be converted to the dipolar ordered state through adiabatic demagnetization in the rotating *** this work,we analyze the spin dynamics of the Hartmann-Hahn CP(HHCP)utilizing the 1 H spin-locking,and the dipolar-order CP(DOCP)having the 1 H adiabatic *** further propose an adiabatic demagnetization CP(ADCP)where a constant radio-frequency pulse is applied on the S spin while 1 H is adiabatically *** analyses indicate that ADCP utilizes the adiabatic passage to effectively achieve the polarization transfer from the 1 H to S *** addition,the dipolar ordered state generated during the 1 H demagnetization process could also be converted into the observable S polarization through DOCP,further enhancing the polarized *** is shown by both static and magic-angle-spinning(MAS)NMR experiments that ADCP has dramatically broadened the CP matching condition over the other CP *** samples have been used to demonstrate the polarization transfer efficiency of this newly proposed ADCP scheme.

关键词： Cross polarization Spin-lock in rotating frame Adiabatic demagnetization Spin dynamics Dipolar ordered state Solid-state NMR

Experimental demonstration of nonlinear quantum metrology with optimal quantum state

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Science Bulletin 2018年第8期63卷 469-476页

作者： Xinfang Nie Jiahao Huang Zhaokai Li Wenqiang Zheng Chaohong Lee xinhua peng Jiangfeng Du CAS Key Laboratory of Microscale Magnetic Resonance and Department of Modern Physics University of Science and Technology of China Hefei National Laboratory for Physical Sciences at Microscale University of Science and Technology of China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China Laboratory of Quantum Engineering and Quantum Metrology School of Physics and Astronomy Sun Yat-sen University (Zhuhai Campus) Center for Optics and Optoelectronics Research College of Science Zhejiang University of Technology State Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-sen University (Guangzhou Campus) Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University

Nonlinear quantum metrology may exhibit better precision scalings. For example, the uncertainty of an estimated phase may scale as △φ∝ 1/N2 under quadratic phase accumulation, which is 1/N times smal-ler than the linear counterpart, where N is probe number. Here, we experimentally demonstrate the non-linear quantum metrology by using a spin-I（I 〉 1/2） nuclear magnetic resonance （NMR） ensemble that can be mapped into a system ofN = 2I spin-1/2 particles and the quadratic interaction can be utilized for the quadratic phase accumulation. Our experimental results show that the phase uncertainty can scale as △φ∝1/（N2-1） by optimizing the input states, when N is an odd number. In addition, the interferomet-tic measurement with quadratic interaction provides a new way for estimating the quadrupolar coupling strength in an NMR system. Our system may be further extended to exotic nonlinear quantum metrology with higher order many-body interactions.

关键词： Quantum information Quantum simulation Quantum metrology Quantum Fisher information Nuclear magnetic resonance Quadrupolar nuclei

Floquet-engineered quantum state transfer in spin chains

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Science Bulletin 2019年第13期64卷 888-895页

作者： Hui Zhou Xi Chen Xinfang Nie Ji Bian Yunlan Ji Zhaokai Li xinhua peng Department of Physics Shaanxi University of Science and TechnologyXi'an 710021China Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics University of Science and Technology of ChinaHefei 230026China CAS Key Laboratory of Microscale Magnetic Resonance University of Science and Technology of ChinaHefei 230026China Department of Physics and Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China

Quantum state transfer between two distant parties is at the heart of quantum computation and quantum *** the various protocols,the counterdiabatic driving(CD)method,by suppressing the unwanted transitions with an auxiliary Hamiltonian Hcd(t),offers a fast and robust strategy to transfer quantum ***,Hcd(t)term often takes a complicated form in higherdimensional systems and is difficult to realize in ***,the Floquet-engineered method was proposed to emulate the dynamics induced by Hcd(t)without the need for complex interactions in multi-qubit systems,which can accelerate the adiabatic process through the fast-oscillating control in the original Hamiltonian H0(t).Here,we apply this method in the Heisenberg spin chains,with only control of the two marginal couplings,to achieve the fast,high-fidelity,and robust quantum state *** we report an experimental implementation of our scheme using a nuclear magnetic resonance *** experimental results demonstrate the feasibility of this method in complex many-body system and thus provide a new alternative to realize the high-fidelity quantum state manipulation in practice.

关键词： Adiabatic quantum optimization Quantum control Quantum state transfer Quantum simulation Nuclear magnetic resonance