Learning the Hamiltonian of a quantum system is indispensable for prediction of the system dynamics and realization of high fidelity quantum gates.However,it is a significant challenge to efficiently characterize the ...Learning the Hamiltonian of a quantum system is indispensable for prediction of the system dynamics and realization of high fidelity quantum gates.However,it is a significant challenge to efficiently characterize the Hamiltonian which has a Hilbert space dimension exponentially growing with the system size.Here,we develop and implement an adaptive method to learn the effective Hamiltonian of an 11-qubit quantum system consisting of one electron spin and ten nuclear spins associated with a single nitrogen-vacancy center in a diamond.We validate the estimated Hamiltonian by designing universal quantum gates based on the learnt Hamiltonian and implementing these gates in the experiment.Our experimental result demonstrates a well-characterized 11-qubit quantum spin register with the ability to test quantum algorithms,and shows our Hamiltonian learning method as a useful tool for characterizing the Hamiltonian of the nodes in a quantum network with solid-state spin qubits.展开更多
Dissipation is often considered as a detrimental effect in quantum systems for unitary quantum operations.However,it has been shown that suitable dissipation can be useful resources in both quantum information and qua...Dissipation is often considered as a detrimental effect in quantum systems for unitary quantum operations.However,it has been shown that suitable dissipation can be useful resources in both quantum information and quantum simulation.Here,we propose and experimentally simulate a dissipative phase transition(DPT)model using a single trapped ion with an engineered reservoir.We show that the ion’s spatial oscillation mode reaches a steady state after the alternating application of unitary evolution under a quantum Rabi model Hamiltonian and sideband cooling of the oscillator.The average phonon number of the oscillation mode is used as the order parameter to provide evidence for the DPT.Our work highlights the suitability of trapped ions for simulating open quantum systems and shall facilitate further investigations of DPT with various dissipation terms.展开更多
Background: The gene for insulin degrading enzyme (IDE) represents a strong positional and biologic candidate for late onset Alzheimer disease (LOAD) susceptibility. IDE is located on chromosome 10q23.3 close to a reg...Background: The gene for insulin degrading enzyme (IDE) represents a strong positional and biologic candidate for late onset Alzheimer disease (LOAD) susceptibility. IDE is located on chromosome 10q23.3 close to a region of linkage for LOAD. In addition, many studies have identi fied a possible role of IDE in the degradation of amyloid β protein and the intracellular amyloid precursor protein (APP) domain released by γ secretase processing. Objective: To examine the association of IDE with AD in the Han Chinese. Methods: Four IDE polymorphisms (three in 5 untranslated region and one in intron 21) were analyzed, using a population of 210 patients with LOAD and 200 control subjects well matched for age, sex, and ethnic background. Results: Among the four polymorphisms studied, only the C allele of single nucleotide polymorphism (SNP) IDE2 showed association with AD (p = 0.005) . Stratification of the data by APOE 4 status indicated that the association between IDE2 and AD was confined to APOE 4 carriers only. No association was found between all variants studied and AD within APOE 4 negative subjects. The global haplotype frequencies showed significant differences between AD patients and control subjects. Furthermore, over representation of GCTG haplotype in the AD group was found. It may be a risk haplotype for AD. Conclusions: These results suggest a possible synergic interaction between IDE and APOE 4 in the risk to develop late onset sporadic AD. IDE might modify the effect of the APOE 4 risk factor in the Han Chinese population.展开更多
Grain-boundary(GB)precipitation has a significant adverse effect on plasticity of alloys,which easily leads to catastrophic intergranular failure in safety-critical applications under high external loading.Herein,we r...Grain-boundary(GB)precipitation has a significant adverse effect on plasticity of alloys,which easily leads to catastrophic intergranular failure in safety-critical applications under high external loading.Herein,we report a novel strategy that uses the local stress concentration induced by GB precipitates as a driving force to trigger phase transformation of preset non-equiatomic high-entropy solid-solution phase at GBs.This in situ deformation-induced phase transformation at GBs introduces a well-known effect:transformation-induced plasticity(TRIP),which enables an exceptional elongation to fracture(above 38%)at a high strength(above 1.5 GPa)in a GB precipitation-hardened high-entropy alloy(HEA).The present strategy in terms of"local stress concentration-induced phase transformations at GBs"may provide a fundamental approach by taking advantage of(rather than avoiding)the GB precipitation to gain a superior combination of high strength and high ductility in HEAs.展开更多
基金Supported by the Frontier Science Center for Quantum Information of the Ministry of Education of China,Tsinghua University Initiative Scientific Research Program,and the National Key Research and Development Program of China(2016YFA0301902)
文摘Learning the Hamiltonian of a quantum system is indispensable for prediction of the system dynamics and realization of high fidelity quantum gates.However,it is a significant challenge to efficiently characterize the Hamiltonian which has a Hilbert space dimension exponentially growing with the system size.Here,we develop and implement an adaptive method to learn the effective Hamiltonian of an 11-qubit quantum system consisting of one electron spin and ten nuclear spins associated with a single nitrogen-vacancy center in a diamond.We validate the estimated Hamiltonian by designing universal quantum gates based on the learnt Hamiltonian and implementing these gates in the experiment.Our experimental result demonstrates a well-characterized 11-qubit quantum spin register with the ability to test quantum algorithms,and shows our Hamiltonian learning method as a useful tool for characterizing the Hamiltonian of the nodes in a quantum network with solid-state spin qubits.
基金supported by the Beijing Academy of Quantum Information Sciencesthe National Key Research and Development Program of China(Grant No.2016YFA0301902)+2 种基金Frontier Science Center for Quantum Information of the Ministry of Education of ChinaTsinghua University Initiative Scientific Research Programsupport from Shuimu Tsinghua Scholar Program and International Postdoctoral Exchange Fellowship Program(Talent-Introduction Program)。
文摘Dissipation is often considered as a detrimental effect in quantum systems for unitary quantum operations.However,it has been shown that suitable dissipation can be useful resources in both quantum information and quantum simulation.Here,we propose and experimentally simulate a dissipative phase transition(DPT)model using a single trapped ion with an engineered reservoir.We show that the ion’s spatial oscillation mode reaches a steady state after the alternating application of unitary evolution under a quantum Rabi model Hamiltonian and sideband cooling of the oscillator.The average phonon number of the oscillation mode is used as the order parameter to provide evidence for the DPT.Our work highlights the suitability of trapped ions for simulating open quantum systems and shall facilitate further investigations of DPT with various dissipation terms.
文摘Background: The gene for insulin degrading enzyme (IDE) represents a strong positional and biologic candidate for late onset Alzheimer disease (LOAD) susceptibility. IDE is located on chromosome 10q23.3 close to a region of linkage for LOAD. In addition, many studies have identi fied a possible role of IDE in the degradation of amyloid β protein and the intracellular amyloid precursor protein (APP) domain released by γ secretase processing. Objective: To examine the association of IDE with AD in the Han Chinese. Methods: Four IDE polymorphisms (three in 5 untranslated region and one in intron 21) were analyzed, using a population of 210 patients with LOAD and 200 control subjects well matched for age, sex, and ethnic background. Results: Among the four polymorphisms studied, only the C allele of single nucleotide polymorphism (SNP) IDE2 showed association with AD (p = 0.005) . Stratification of the data by APOE 4 status indicated that the association between IDE2 and AD was confined to APOE 4 carriers only. No association was found between all variants studied and AD within APOE 4 negative subjects. The global haplotype frequencies showed significant differences between AD patients and control subjects. Furthermore, over representation of GCTG haplotype in the AD group was found. It may be a risk haplotype for AD. Conclusions: These results suggest a possible synergic interaction between IDE and APOE 4 in the risk to develop late onset sporadic AD. IDE might modify the effect of the APOE 4 risk factor in the Han Chinese population.
基金supported financially by the National Natural Science Foundation of China(No.51871178)。
文摘Grain-boundary(GB)precipitation has a significant adverse effect on plasticity of alloys,which easily leads to catastrophic intergranular failure in safety-critical applications under high external loading.Herein,we report a novel strategy that uses the local stress concentration induced by GB precipitates as a driving force to trigger phase transformation of preset non-equiatomic high-entropy solid-solution phase at GBs.This in situ deformation-induced phase transformation at GBs introduces a well-known effect:transformation-induced plasticity(TRIP),which enables an exceptional elongation to fracture(above 38%)at a high strength(above 1.5 GPa)in a GB precipitation-hardened high-entropy alloy(HEA).The present strategy in terms of"local stress concentration-induced phase transformations at GBs"may provide a fundamental approach by taking advantage of(rather than avoiding)the GB precipitation to gain a superior combination of high strength and high ductility in HEAs.
