ON SPHERICALLY SYMMETRIC FINSLER METRICS WITH ISOTROPIC BERWALD CURVATURE

2013 ◽  
Vol 10 (10) ◽  
pp. 1350054 ◽  
Author(s):  
ENLI GUO ◽  
HUAIFU LIU ◽  
XIAOHUAN MO
Keyword(s):  
Orthogonal Group ◽  
Finsler Metric ◽  
Finsler Metrics ◽  
Spherically Symmetric ◽  
Randers Metric

A Finsler metric F is said to be spherically symmetric if the orthogonal group O(n) acts as isometries of F. In this paper, we show that every spherically symmetric Finsler metric of isotropic Berwald curvature is a Randers metric. We also construct explicitly a lot of new isotropic Berwald spherically symmetric Finsler metrics.

Projective Ricci flat spherically symmetric Finsler metrics

2018 ◽  
Vol 29 (11) ◽  
pp. 1850078 ◽  
Author(s):  
Hongmei Zhu ◽  
Haixia Zhang
Keyword(s):  
Ricci Curvature ◽  
Finsler Geometry ◽  
Finsler Metric ◽  
Finsler Metrics ◽  
Spherically Symmetric ◽  
Projective Invariant ◽  
Ricci Flat ◽  
Douglas Metric

In Finsler geometry, the projective Ricci curvature is an important projective invariant. In this paper, we characterize projective Ricci flat spherically symmetric Finsler metrics. Under a certain condition, we prove that a projective Ricci flat spherically symmetric Finsler metric must be a Douglas metric. Moreover, we construct a class of new nontrivial examples on projective Ricci flat Finsler metrics.

A geometric approach to quantum circuit lower bounds

2006 ◽  
Vol 6 (3) ◽  
pp. 213-262 ◽  
Author(s):  
M.A. Nielsen
Keyword(s):  
Lower Bounds ◽  
Geometric Approach ◽  
Quantum Circuit ◽  
Geodesic Equation ◽  
Initial Position ◽  
Minimal Length ◽  
Finsler Metric ◽  
Finsler Metrics ◽  
Minimal Size ◽  
Circuit Lower Bounds

What is the minimal size quantum circuit required to exactly implement a specified n-qubit unitary operation, U, without the use of ancilla qubits? We show that a lower bound on the minimal size is provided by the length of the minimal geodesic between U and the identity, I, where length is defined by a suitable Finsler metric on the manifold SU(2^n). The geodesic curves on these manifolds have the striking property that once an initial position and velocity are set, the remainder of the geodesic is completely determined by a second order differential equation known as the geodesic equation. This is in contrast with the usual case in circuit design, either classical or quantum, where being given part of an optimal circuit does not obviously assist in the design of the rest of the circuit. Geodesic analysis thus offers a potentially powerful approach to the problem of proving quantum circuit lower bounds. In this paper we construct several Finsler metrics whose minimal length geodesics provide lower bounds on quantum circuit size. For each Finsler metric we give a procedure to compute the corresponding geodesic equation. We also construct a large class of solutions to the geodesic equation, which we call \emph{Pauli geodesics}, since they arise from isometries generated by the Pauli group. For any unitary U diagonal in the computational basis, we show that: (a) provided the minimal length geodesic is unique, it must be a Pauli geodesic; (b) finding the length of the minimal Pauli geodesic passing from I to U is equivalent to solving an exponential size instance of the closest vector in a lattice problem (CVP); and (c) all but a doubly exponentially small fraction of such unitaries have minimal Pauli geodesics of exponential length.

Finsler Metrics with K = 0 and S = 0

2003 ◽  
Vol 55 (1) ◽  
pp. 112-132 ◽  
Author(s):  
Zhongmin Shen
Keyword(s):  
Euclidean Space ◽  
Shortest Path ◽  
External Force ◽  
Riemannian Space ◽  
Shortest Path Problem ◽  
Flag Curvature ◽  
Finsler Metrics ◽  
Randers Metric ◽  
Randers Space ◽  
Time Problem

AbstractIn the paper, we study the shortest time problem on a Riemannian space with an external force. We show that such problem can be converted to a shortest path problem on a Randers space. By choosing an appropriate external force on the Euclidean space, we obtain a non-trivial Randers metric of zero flag curvature. We also show that any positively complete Randers metric with zero flag curvature must be locally Minkowskian.

scholarly journals On spherically symmetric Finsler metrics with vanishing Douglas curvature

2013 ◽  
Vol 31 (6) ◽  
pp. 746-758 ◽  
Author(s):  
Xiaohuan Mo ◽  
Newton Mayer Solórzano ◽  
Keti Tenenblat
Keyword(s):  
Finsler Metrics ◽  
Spherically Symmetric ◽  
Douglas Curvature

scholarly journals A NEW QUANTITY IN RIEMANN-FINSLER GEOMETRY

2012 ◽  
Vol 54 (3) ◽  
pp. 637-645 ◽  
Author(s):  
XIAOHUAN MO ◽  
ZHONGMIN SHEN ◽  
HUAIFU LIU
Keyword(s):  
Scalar Curvature ◽  
Simple Proof ◽  
Finsler Geometry ◽  
Finsler Manifold ◽  
Flag Curvature ◽  
Finsler Metric ◽  
Finsler Metrics ◽  
Riemannian Curvature

AbstractIn this note, we study a new Finslerian quantity Ĉ defined by the Riemannian curvature. We prove that the new Finslerian quantity is a non-Riemannian quantity for a Finsler manifold with dimension n = 3. Then we study Finsler metrics of scalar curvature. We find that the Ĉ-curvature is closely related to the flag curvature and the H-curvature. We show that Ĉ-curvature gives, a measure of the failure of a Finsler metric to be of weakly isotropic flag curvature. We also give a simple proof of the Najafi-Shen-Tayebi' theorem.

scholarly journals Spherically symmetric Finsler metrics with constant Ricci and flag curvature

2015 ◽  
Vol 87 (3-4) ◽  
pp. 463-472 ◽  
Author(s):  
ESRA SENGELEN SEVIM ◽  
ZHONGMIN SHEN ◽  
SEMAIL ULGEN
Keyword(s):  
Flag Curvature ◽  
Finsler Metrics ◽  
Spherically Symmetric

scholarly journals Homogeneous Finsler spaces and the flag-wise positively curved condition

2018 ◽  
Vol 30 (6) ◽  
pp. 1521-1537
Author(s):  
Ming Xu ◽  
Shaoqiang Deng
Keyword(s):  
Lie Algebra ◽  
Tangent Plane ◽  
Finsler Metric ◽  
Finsler Metrics ◽  
Finsler Spaces ◽  
Negatively Curved ◽  
Hopf Conjecture ◽  
Coset Spaces ◽  
Positive Flag Curvature ◽  
Positively Curved

Abstract In this paper, we introduce the flag-wise positively curved condition for Finsler spaces (the (FP) condition), which means that in each tangent plane, there exists a flag pole in this plane such that the corresponding flag has positive flag curvature. Applying the Killing navigation technique, we find a list of compact coset spaces admitting non-negatively curved homogeneous Finsler metrics satisfying the (FP) condition. Using a crucial technique we developed previously, we prove that most of these coset spaces cannot be endowed with positively curved homogeneous Finsler metrics. We also prove that any Lie group whose Lie algebra is a rank 2 non-Abelian compact Lie algebra admits a left invariant Finsler metric satisfying the (FP) condition. As by-products, we find the first example of non-compact coset space {S^{3}\times\mathbb{R}} which admits homogeneous flag-wise positively curved Finsler metrics. Moreover, we find some non-negatively curved Finsler metrics on {S^{2}\times S^{3}} and {S^{6}\times S^{7}} which satisfy the (FP) condition, as well as some flag-wise positively curved Finsler metrics on {S^{3}\times S^{3}} , shedding some light on the long standing general Hopf conjecture.

Finsler Warped Product Metrics of Douglas Type

2019 ◽  
Vol 62 (1) ◽  
pp. 119-130 ◽  
Author(s):  
Huaifu Liu ◽  
Xiaohuan Mo
Keyword(s):  
Differential Equation ◽  
Warped Product ◽  
Finsler Metrics ◽  
Spherically Symmetric ◽  
Product Metrics ◽  
Douglas Curvature

AbstractIn this paper, we study the warped structures of Finsler metrics. We obtain the differential equation that characterizes Finsler warped product metrics with vanishing Douglas curvature. By solving this equation, we obtain all Finsler warped product Douglas metrics. Some new Douglas Finsler metrics of this type are produced by using known spherically symmetric Douglas metrics.

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