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Quantum computing is a promising new area of computing with quantum algorithms offering a potential speedup over classical algorithms if fault tolerant quantum computers can be built. One of the first applications of the classical computer…

Quantum Physics · Physics 2023-03-09 Michael McGuigan

Else from the quotient algebra partition considered in the preceding episodes, two kinds of partitions on unitary Lie algebras are created by nonabelian bi-subalgebras. It is of interest that there exists a partition duality between the two…

Mathematical Physics · Physics 2019-12-10 Zheng-Yao Su , Ming-Chung Tsai

The quantum Fourier transform (QFT) is a powerful tool in quantum computing. The main ingredients of QFT are formed by the Walsh-Hadamard transform H and phase shifts P(.), both of which are 2x2 unitary matrices as operators on the…

Quantum Physics · Physics 2007-05-23 Charles M. Bowden , Goong Chen , Zijian Diao , Andreas Klappenecker

Averaging physical quantities over Lie groups appears in many contexts across the rapidly developing branches of physics like quantum information science or quantum optics. Such an averaging process can be always represented as averaging…

Quantum Physics · Physics 2021-07-07 Marcin Markiewicz , Janusz Przewocki

We propose to represent both $n$--qubits and quantum gates acting on them as elements in the complex Clifford algebra defined on a complex vector space of dimension $2n.$ In this framework, the Dirac formalism can be realized in…

Quantum Physics · Physics 2022-03-04 Jaroslav Hrdina , Ales Navrat , Petr Vasik

Quantum computers can efficiently solve problems which are widely believed to lie beyond the reach of classical computers. In the near-term, hybrid quantum-classical algorithms, which efficiently embed quantum hardware in classical…

Quantum Physics · Physics 2026-05-07 Ananda Roy , Robert M. Konik , David Rogerson

Although only two quantum states of a physical system are often used to encode quantum information in the form of qubits, many levels can in principle be used to obtain qudits and increase the information capacity of the system. To take…

Quantum Physics · Physics 2025-06-25 Aryan Iliat , Mark Byrd , Sahel Ashhab , LianAo Wu

In [2], an exhaustive construction is achieved for the class of all 4-dimensional unital division algebras over finite fields of odd order, whose left nucleus is not minimal and whose automorphism group contains Klein's four-group. We…

Rings and Algebras · Mathematics 2019-08-20 Ernst Dieterich

We provide a method for compiling approximate multi-controlled single qubit gates into quantum circuits without ancilla qubits. The total number of elementary gates to decompose an n-qubit multi-controlled gate is proportional to 32n, and…

Cylindrical Algebraic Decomposition (CAD) has long been one of the most important algorithms within Symbolic Computation, as a tool to perform quantifier elimination in first order logic over the reals. More recently it is finding…

Symbolic Computation · Computer Science 2020-03-23 Matthew England , Russell Bradford , James H. Davenport

We define Cartan subgroups in connected locally compact groups, which extends the classical notion of Cartan subgroups in Lie groups. We prove their existence and justify our choice of the definition which differs from the one given by…

Group Theory · Mathematics 2026-04-15 Arunava Mandal , Riddhi Shah

Recently it has been shown that time-optimal quantum computation is attained by using the Cartan decomposition of a unitary matrix. We extend this approach by noting that the unitary group is compact. This allows us to reduce the execution…

Quantum Physics · Physics 2007-05-23 Mikio Nakahara , Juha J. Vartiainen , Yasushi Kondo , Shogo Tanimura , Kazuya Hata

Using methods coming from non-formal equivariant quantization, we construct in this short note a unitary dual 2-cocycle on a discrete family of quotient groups of subgroups of the affine group of a local field (which is not of…

Operator Algebras · Mathematics 2018-09-26 David Jondreville

We introduce the flag decomposition as a central tool for unitary synthesis. It lets us carve out a diagonal unitary with $2^n$ degrees of freedom in such a way that the remaining flag circuit is parametrized by the optimal number of…

Quantum Physics · Physics 2026-03-24 Korbinian Kottmann , David Wierichs , Guillermo Alonso-Linaje , Nathan Killoran

The quantum Fourier transform (QFT) plays an important role in many known quantum algorithms such as Shor's algorithm for prime factorisation. In this paper we show that the QFT algorithm can, on a restricted set of input states, be…

Quantum Physics · Physics 2020-01-27 Alastair A. Abbott

Using the natural irreducible 8-dimensional representation and the two spin representations of the quantum group $U_q$(D$_4$) of D$_4$, we construct a quantum analogue of the split octonions and study its properties. We prove that the…

Quantum Algebra · Mathematics 2016-09-07 Georgia Benkart , José M. Pérez-Izquierdo

A generalization of the differential geometry of forms and vector fields to the case of quantum Lie algebras is given. In an abstract formulation that incorporates many existing examples of differential geometry on quantum spaces we combine…

High Energy Physics - Theory · Physics 2007-05-23 Peter Schupp , Paul Watts , Bruno Zumino

We present a simple and fast numerical procedure to search for good quantum codes for storing logical qubits in the presence of independent per-qubit noise. In a key departure from past work, we use the worst-case fidelity as the figure of…

Quantum Physics · Physics 2020-04-13 Akshaya Jayashankar , Anjala M Babu , Hui Khoon Ng , Prabha Mandayam

We show that an n-th root of the Walsh-Hadamard transform (obtained from the Hadamard gate and a cyclic permutation of the qubits), together with two diagonal matrices, namely a local qubit-flip (for a fixed but arbitrary qubit) and a…

Quantum Physics · Physics 2007-05-23 Simone Severini

Decoupling theorems have proven useful in various applications in the area of quantum information theory. This thesis builds upon preceding work by Fr\'{e}d\'{e}ric Dupuis [arXiv:1012.6044v1], where a general decoupling theorem is obtained…

Quantum Physics · Physics 2012-07-18 Oleg Szehr