Geometric quantum discord（GQD） and Berry phase between two charge qubits coupled by a quantum transmission line are investigated. We show how GQDs evolve and investigate their dependencies on the parameters of the s...Geometric quantum discord（GQD） and Berry phase between two charge qubits coupled by a quantum transmission line are investigated. We show how GQDs evolve and investigate their dependencies on the parameters of the system.We also calculate the energy and the Berry phase and compare them with GQD, finding that there are close connections between them.展开更多
In the mean-field theory of atom-molecule systems, where the bosonic atoms combine to form molecules, there is no usual U（1） symmetry, which presents an apparent hurdle for calculating the Berry connection in these ...In the mean-field theory of atom-molecule systems, where the bosonic atoms combine to form molecules, there is no usual U（1） symmetry, which presents an apparent hurdle for calculating the Berry connection in these systems. We develop a perturbation expansion method of Hannay＇s angle suitable for calculating the Berry curvature in the atom- molecule systems. With this Berry curvature, the Berry connection can be computed naturally. We use a three-level atom-molecule system to illustrate our results. In particular, with this method, we compute the curvature for Hannay＇s angle analytically, and compare it to the Berry curvature obtained with the second-quantized model of the same system. An excellent agreement is found, indicating the validity of our method.展开更多
We propose a method for generating double-ring-shaped vector beams. A step phase introduced by a spatial light modulator（SLM） first makes the incident laser beam have a nodal cycle. This phase is dynamic in nature b...We propose a method for generating double-ring-shaped vector beams. A step phase introduced by a spatial light modulator（SLM） first makes the incident laser beam have a nodal cycle. This phase is dynamic in nature because it depends on the optical length. Then a Pancharatnam–Berry phase（PBP） optical element is used to manipulate the local polarization of the optical field by modulating the geometric phase. The experimental results show that this scheme can effectively create double-ring-shaped vector beams. It provides much greater flexibility to manipulate the phase and polarization by simultaneously modulating the dynamic and the geometric phases.展开更多
Nature has developed codon as a tool to manipulate a two-electron spin symmetry (short-living electrons, forming a radical pair, arise from the Mg-bound nucleosidetriphosphate cleavage at the triplet/singlet (T/S) cro...Nature has developed codon as a tool to manipulate a two-electron spin symmetry (short-living electrons, forming a radical pair, arise from the Mg-bound nucleosidetriphosphate cleavage at the triplet/singlet (T/S) crossing), which permits or forbids further nucleotide synthesis (DNA/RNA) and the synthesis of proteins. The thesis is confirmed by conducting DFT:B3LYP (6-311G** basis set) computations (T/S potential energy surfaces) with the model system composed of the template (C-G-C-G-A nucleotide sequence) and the growing chain (G-C-G nucleotide sequence, DNA or RNA). The origin of codon is in hyperfine interaction between a single electron, transferred onto the template, and three 31P nuclei built into the phosphorus fragments of nucleotides. The nuclei, together with the polynucleotide structure, form a spiral twist that is homeomorphic to a triangle patch on the Poincare sphere. Each triangle has unique angle values depending on the nucleotide nature and their position in the codon. The patch tracing produces the Berry phase changing the electron spin orientation from “up” to “down”. The Berry phase accumulation proceeds around the (T/S) conical intersections (CIs). The CIs are a result of complementary recognition between nucleotide bases at distances exceeding the commonly accepted Watson-Crick pairing by 0.17 A. Upon changing spin symmetry, the DNA or RNA chain is allowed to elongate by attaching a newly coming nucleotide. Without complementary recognition between the bases, the chain stops its elongation. The Berry phase accumulation along the patch tracing explains the effect of Crick’s wobbling when the second nucleotide plays a primary role in recognition. The data is directly linked to creation of a quantum computing device.展开更多
The geometric phase is regarded as a promising strategy in fault tolerance quantum information processing(QIP) domain due to its phase only depending on the geometry of the path executed. However, decoherence caused b...The geometric phase is regarded as a promising strategy in fault tolerance quantum information processing(QIP) domain due to its phase only depending on the geometry of the path executed. However, decoherence caused by environmental noise will destroy the geometric phase. Traditional dynamic decoupling sequences can eliminate dynamic dephasing but can not reduce residual geometric dephasing, which is still vital for high-precision quantum manipulation. In this work, we experimentally demonstrate effective suppression of residual geometric dephasing with modified dynamic decoupling schemes,using a single trapped171 Ybtion. The experimental results show that the modified schemes can reduce dephasing rate up to more than one order of magnitude compared with traditional dynamic decoupling schemes, where residual geometric dephasing dominates. Besides, we also investigate the impact of intensity and correlation time of the low-frequency noise on coherence of the quantum system. And we confirm these methods can be used in many cases.展开更多
In this pedagogically oriented review,we discuss the concept of Berry phase in quantum physics,paying particular attention to their manifestation in Bloch electrons.We have discussed,within the limited scope and passa...In this pedagogically oriented review,we discuss the concept of Berry phase in quantum physics,paying particular attention to their manifestation in Bloch electrons.We have discussed,within the limited scope and passage,a few examples to illustrate the rich and fascinating manifestations of Berry phase in our understanding of many a physical property of a wide range of materials,including optoelectronic responses and quantum transport properties.It is also demonstrated that various topological phases of current interest are characterized by topological numbers,which are in fact incarnations of the Berry phase.A discussion of various techniques for gauge fixing,which may be important to the computation of Berry phase related properties,is also included.展开更多
At present, Berry’s topological phase factor and the studies of its relevant problem have drawn considerable attention . It concerns the theoretical analysis of chiral anomaly, etc., which is also experimentally conf...At present, Berry’s topological phase factor and the studies of its relevant problem have drawn considerable attention . It concerns the theoretical analysis of chiral anomaly, etc., which is also experimentally confirmed. In general, the explicit determination of the展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11174024)the State Key Laboratory of Low-Dimensional Quantum Physics(Tsinghua University)(Grant No.KF201407)+1 种基金the Fundamental Research Funds for the Central Universities of Beihang University(Grant No.YWF-14-WLXY-017)Beijing City Youth Talent Plan
文摘Geometric quantum discord（GQD） and Berry phase between two charge qubits coupled by a quantum transmission line are investigated. We show how GQDs evolve and investigate their dependencies on the parameters of the system.We also calculate the energy and the Berry phase and compare them with GQD, finding that there are close connections between them.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10825417)
文摘In the mean-field theory of atom-molecule systems, where the bosonic atoms combine to form molecules, there is no usual U（1） symmetry, which presents an apparent hurdle for calculating the Berry connection in these systems. We develop a perturbation expansion method of Hannay＇s angle suitable for calculating the Berry curvature in the atom- molecule systems. With this Berry curvature, the Berry connection can be computed naturally. We use a three-level atom-molecule system to illustrate our results. In particular, with this method, we compute the curvature for Hannay＇s angle analytically, and compare it to the Berry curvature obtained with the second-quantized model of the same system. An excellent agreement is found, indicating the validity of our method.
基金Project supported by the National Natural Science Foundation of China(Grant No.11547017)the Hubei Engineering University Research Foundation,China(Grant No.z2014001)the Natural Science Foundation of Hubei Province,China(Grant No.2014CFB578)
文摘We propose a method for generating double-ring-shaped vector beams. A step phase introduced by a spatial light modulator（SLM） first makes the incident laser beam have a nodal cycle. This phase is dynamic in nature because it depends on the optical length. Then a Pancharatnam–Berry phase（PBP） optical element is used to manipulate the local polarization of the optical field by modulating the geometric phase. The experimental results show that this scheme can effectively create double-ring-shaped vector beams. It provides much greater flexibility to manipulate the phase and polarization by simultaneously modulating the dynamic and the geometric phases.
文摘Nature has developed codon as a tool to manipulate a two-electron spin symmetry (short-living electrons, forming a radical pair, arise from the Mg-bound nucleosidetriphosphate cleavage at the triplet/singlet (T/S) crossing), which permits or forbids further nucleotide synthesis (DNA/RNA) and the synthesis of proteins. The thesis is confirmed by conducting DFT:B3LYP (6-311G** basis set) computations (T/S potential energy surfaces) with the model system composed of the template (C-G-C-G-A nucleotide sequence) and the growing chain (G-C-G nucleotide sequence, DNA or RNA). The origin of codon is in hyperfine interaction between a single electron, transferred onto the template, and three 31P nuclei built into the phosphorus fragments of nucleotides. The nuclei, together with the polynucleotide structure, form a spiral twist that is homeomorphic to a triangle patch on the Poincare sphere. Each triangle has unique angle values depending on the nucleotide nature and their position in the codon. The patch tracing produces the Berry phase changing the electron spin orientation from “up” to “down”. The Berry phase accumulation proceeds around the (T/S) conical intersections (CIs). The CIs are a result of complementary recognition between nucleotide bases at distances exceeding the commonly accepted Watson-Crick pairing by 0.17 A. Upon changing spin symmetry, the DNA or RNA chain is allowed to elongate by attaching a newly coming nucleotide. Without complementary recognition between the bases, the chain stops its elongation. The Berry phase accumulation along the patch tracing explains the effect of Crick’s wobbling when the second nucleotide plays a primary role in recognition. The data is directly linked to creation of a quantum computing device.
基金supported by the National Key Research and Development Program of China (2016YFA0302700)Anhui Initiative in Quantum Information Technologies (AHY070000)+3 种基金Key Research Program of Frontier Sciences, CAS (QYZDY-SSWSLH003)National Natural Science Foundation of China (11474268, 11574294, 11734015, 11474270 and 11404319)the Fundamental Research Funds for the Central Universities (WK2470000026, WK2470000027 and WK2470000028)the Anhui Provincial Natural Science Foundation (1608085QA22)
文摘The geometric phase is regarded as a promising strategy in fault tolerance quantum information processing(QIP) domain due to its phase only depending on the geometry of the path executed. However, decoherence caused by environmental noise will destroy the geometric phase. Traditional dynamic decoupling sequences can eliminate dynamic dephasing but can not reduce residual geometric dephasing, which is still vital for high-precision quantum manipulation. In this work, we experimentally demonstrate effective suppression of residual geometric dephasing with modified dynamic decoupling schemes,using a single trapped171 Ybtion. The experimental results show that the modified schemes can reduce dephasing rate up to more than one order of magnitude compared with traditional dynamic decoupling schemes, where residual geometric dephasing dominates. Besides, we also investigate the impact of intensity and correlation time of the low-frequency noise on coherence of the quantum system. And we confirm these methods can be used in many cases.
基金supported by the National Natural Science Foundation of China(Grant No.11725415)
文摘In this pedagogically oriented review,we discuss the concept of Berry phase in quantum physics,paying particular attention to their manifestation in Bloch electrons.We have discussed,within the limited scope and passage,a few examples to illustrate the rich and fascinating manifestations of Berry phase in our understanding of many a physical property of a wide range of materials,including optoelectronic responses and quantum transport properties.It is also demonstrated that various topological phases of current interest are characterized by topological numbers,which are in fact incarnations of the Berry phase.A discussion of various techniques for gauge fixing,which may be important to the computation of Berry phase related properties,is also included.
基金Project supported by the National Natural Science Foundation of China.
文摘At present, Berry’s topological phase factor and the studies of its relevant problem have drawn considerable attention . It concerns the theoretical analysis of chiral anomaly, etc., which is also experimentally confirmed. In general, the explicit determination of the
