Expressibility, entangling power, and quantum average causal effect for causally indefinite circuits
Parameterized quantum circuits are the core of new technologies such as variational quantum algorithms and quantum machine learning, which makes studying its properties a valuable task. We implement parameterized circuits with definite and indefinite causal order and compare their performance under particular descriptors. One of these is the expressibility, which measures how uniformly a given quantum circuit can reach the whole Hilbert space. Another property that we focus on this work is the entanglement capability, more specifically the concurrence and the entangling power. We also find the causal relation between the qubits of our system with the quantum average causal effect measure. We have found that indefinite circuits offer expressibility advantages over definite ones while maintaining the level of entanglement generation. Our results also point to the existence of a correlation between the quantum average causal effect and the entangling power.
Authors
- Alexandre Drinko (ORCID: https://orcid.org/0000-0001-6422-8395)
- Diogo O. Soares-Pinto (ORCID: https://orcid.org/0000-0002-4293-6144)
- Guilherme I. Correr (ORCID: https://orcid.org/0000-0002-8444-3567)
- Askery Canabarro (ORCID: https://orcid.org/0000-0001-5048-2317)
- Pedro C. Azado (ORCID: https://orcid.org/0000-0001-7319-9098)
- Ivan Medina (ORCID: https://orcid.org/0000-0001-6428-2826)
Institutions
- University of Helsinki (FI)
- Universidade de São Paulo (BR)
- Trinity College Dublin (IE)
- Harvard University Press (US)
- Technology Innovation Institute (AE)
- International Iberian Nanotechnology Laboratory (PT)
- Universidade Federal de Alagoas (BR)
Publication Details
- Journal
- Physical review. A/Physical review, A
- Published
- 2025-04-25
- DOI
- https://doi.org/10.1103/physreva.111.042620
- Citations
- 1
- Primary Topic
- Quantum Computing Algorithms and Architecture
- Type
- article
- Field-Weighted Citation Impact
- 2.48
Funders
- Fundação de Amparo à Pesquisa do Estado de São Paulo
- Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
- Academy of Finland
- Fundação de Amparo à Pesquisa do Estado de Alagoas
- Conselho Nacional de Desenvolvimento Científico e Tecnológico
- Universidade de São Paulo
- Instituto Nacional de Ciência e Tecnologia de Informação Quântica