Quantum Coherence of Critical Unstable Two-Level Systems
Fuente:
arXiv
Guardado en:
| Autores principales: | , , |
|---|---|
| Formato: | Preprint |
| Publicado: |
2022
|
| Materias: | |
| Acceso en línea: | |
| Etiquetas: |
Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
|
| _version_ | 1866909126193315840 |
|---|---|
| author | Karamitros, Dimitrios McKelvey, Thomas Pilaftsis, Apostolos |
| author_facet | Karamitros, Dimitrios McKelvey, Thomas Pilaftsis, Apostolos |
| contents | We study in detail the dynamics of unstable two-level quantum systems by adopting the Bloch-sphere formalism of qubits. By employing the Bloch-vector representation for such unstable qubit systems, we identify a novel class of critical scenarios in which the so-called energy-level and decay-width vectors, ${\bf E}$ and ${\bfΓ}$, are orthogonal to one another, and the parameter $r = |{\bf Γ}|/(2|{\bf E}|)$ is less than 1. Most remarkably, we find that critical unstable qubit systems exhibit atypical behaviours like coherence--decoherence oscillations when analysed in an appropriately defined co-decaying frame of the system. In the same frame, a unit Bloch vector ${\bf b}$ describing a pure critical qubit will sweep out unequal areas during equal intervals of time, while rotating about the vector ${\bf E}$. These phenomena emerge beyond the usual oscillatory pattern due to the energy-level difference of the two-level quantum system. Interestingly enough, we observe that these new features will persist even for quasi-critical scenarios, in which the vectors ${\bf E}$ and ${\bfΓ}$ are not perfectly orthogonal to each other. Applications of our results to quantum information and to unstable meson--antimeson and other systems are discussed. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2212_06031 |
| institution | arXiv |
| publishDate | 2022 |
| record_format | arxiv |
| spellingShingle | Quantum Coherence of Critical Unstable Two-Level Systems Karamitros, Dimitrios McKelvey, Thomas Pilaftsis, Apostolos High Energy Physics - Phenomenology High Energy Physics - Theory Quantum Physics We study in detail the dynamics of unstable two-level quantum systems by adopting the Bloch-sphere formalism of qubits. By employing the Bloch-vector representation for such unstable qubit systems, we identify a novel class of critical scenarios in which the so-called energy-level and decay-width vectors, ${\bf E}$ and ${\bfΓ}$, are orthogonal to one another, and the parameter $r = |{\bf Γ}|/(2|{\bf E}|)$ is less than 1. Most remarkably, we find that critical unstable qubit systems exhibit atypical behaviours like coherence--decoherence oscillations when analysed in an appropriately defined co-decaying frame of the system. In the same frame, a unit Bloch vector ${\bf b}$ describing a pure critical qubit will sweep out unequal areas during equal intervals of time, while rotating about the vector ${\bf E}$. These phenomena emerge beyond the usual oscillatory pattern due to the energy-level difference of the two-level quantum system. Interestingly enough, we observe that these new features will persist even for quasi-critical scenarios, in which the vectors ${\bf E}$ and ${\bfΓ}$ are not perfectly orthogonal to each other. Applications of our results to quantum information and to unstable meson--antimeson and other systems are discussed. |
| title | Quantum Coherence of Critical Unstable Two-Level Systems |
| topic | High Energy Physics - Phenomenology High Energy Physics - Theory Quantum Physics |
| url | https://arxiv.org/abs/2212.06031 |