Search arXivSearch

arXiv · 0905.1428

SIC-POVMs and MUBs: Geometrical Relationships in Prime Dimension

Abstract

The paper concerns Weyl-Heisenberg covariant SIC-POVMs (symmetric informationally complete positive operator valued measures) and full sets of MUBs (mutually unbiased bases) in prime dimension. When represented as vectors in generalized Bloch space a SIC-POVM forms a d^2-1 dimensional regular simplex (d being the Hilbert space dimension). By contrast, the generalized Bloch vectors representing a full set of MUBs form d+1 mutually orthogonal d-1 dimensional regular simplices. In this paper we show that, in the Weyl-Heisenberg case, there are some simple geometrical relationships between the single SIC-POVM simplex and the d+1 MUB simplices. We go on to give geometrical interpretations of the minimum uncertainty states introduced by Wootters and Sussman, and by Appleby, Dang and Fuchs, and of the fiduciality condition given by Appleby, Dang and Fuchs.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

D. M. Appleby. 2009-05-09. SIC-POVMs and MUBs: Geometrical Relationships in Prime Dimension. https://doi.org/10.1063/1.3109944

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Centralised multi link measurement compression with side information

We prove new one shot achievability results for measurement compression of quantum instruments with side information at the receiver. Unlike previous one shot results for this problem, our one shot bounds are nearly optimal and do not need catalytic randomness. In fact, we state a more general problem called centralised multi link measurement compression with quantum side information and provide one shot achievability results for it. As a simple corollary, we obtain one shot measurement compression results for quantum instruments with side information that we mentioned earlier. All our one shot results lead to the standard results for this problem in the asymptotic iid setting. We prove our achievability bounds by first proving a novel sequential classical quantum multipartite covering lemma, which should be of independent interest.

quant-ph

Perfect quantum reflection from a cliff: a potential unbounded from below

We explain how a potential that is well-defined everywhere on the positive half-line, but is nowhere positive and diverges to $-\infty$ as $x\rightarrow 0^+$, can nevertheless confine a particle to the half-line and lead to well-defined dynamics. Such perfect reflection from a "cliff" potential is achieved by a purely dynamical mechanism, without the need to impose any boundary conditions at the edge. We discuss in detail the role of self-adjointness in ensuring dynamical closure at the quantum level, and advocate the principle that, when no boundary conditions or other physical data are given, the formal quantized Hamiltonian is most naturally defined on its maximal domain. We then construct an explicit cliff potential with the claimed properties, showing that the Hamiltonian is self-adjoint on this maximal domain and therefore defines a dynamically closed quantum system. Finally, we study its energy eigenstates, spectrum, and the phase shift associated with the reflection.

quant-ph

AC/DC: Automated Compilation for Dynamic Circuits

Dynamic quantum circuits incorporate mid-circuit measurements (MCMs) and feed-forward operations are crucial for manipulating quantum information. They have been broadly used in quantum error correction and quantum teleportation. Recently, they are utilized to prepare certain states and long-range entangling gates as well as reduce resource overhead in quantum algorithms. In this paper, we present AC/DC, a novel Automated Compilation framework for generating Dynamic quantum Circuits that prepare any unitary operators or states, leveraging numerical optimization-based circuit synthesis methods. The first contribution is introducing optimization objective functions incorporating MCMs and feed-forward operations. The second contribution is embedding these into a popular open-source quantum circuit synthesis framework. We demonstrate generating dynamic circuits for long range entangling gates, circuit optimization, lattice simulations, and state preparation, with validation through simulation and quantum hardware. Furthermore, we perform a noise analysis to assess the impact of MCM and gate errors, identifying scenarios where dynamic circuits provide significant benefits. The dynamic circuits generated by our framework show substantial improvements in reducing circuit depth and, in some cases, the number of gates. To our knowledge, this is the first practical procedure to generate dynamic quantum circuits, paving the way for enhanced circuit generation and optimization methods for near-term quantum computers.

quant-ph