Squeezing of Primordial Gravitational Waves as Quantum Discord
We investigate the squeezing of primordial gravitational waves (PGWs) in terms of quantum discord. We construct a classical state of PGWs without quantum discord and compare it with the Bunch−Davies vacuum. Then it is shown that the oscillatory behavior of the angular-power spectrum of the...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2020-02-01
|
| Series: | Universe |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2218-1997/6/2/33 |
| _version_ | 1817996940015566848 |
|---|---|
| author | Akira Matsumura Yasusada Nambu |
| author_facet | Akira Matsumura Yasusada Nambu |
| author_sort | Akira Matsumura |
| collection | DOAJ |
| description | We investigate the squeezing of primordial gravitational waves (PGWs) in terms of quantum discord. We construct a classical state of PGWs without quantum discord and compare it with the Bunch−Davies vacuum. Then it is shown that the oscillatory behavior of the angular-power spectrum of the cosmic microwave background (CMB) fluctuations induced by PGWs can be the signature of the quantum discord of PGWs. In addition, we discuss the effect of quantum decoherence on the entanglement and the quantum discord of PGWs for super-horizon modes. For the state of PGWs with decoherence effect, we examine the decoherence condition and the correlation condition introduced by C. Kiefer et al. (<i>Class. Quantum Grav.</i> <b>24</b> (2007) 1699). We show that the decoherence condition is not sufficient for the separability of PGWs and the correlation condition implies that the PGWs in the matter-dominated era have quantum discord. |
| first_indexed | 2024-04-14T02:29:43Z |
| format | Article |
| id | doaj.art-3c65dddd321342099217a9f409bc354e |
| institution | Directory Open Access Journal |
| issn | 2218-1997 |
| language | English |
| last_indexed | 2024-04-14T02:29:43Z |
| publishDate | 2020-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Universe |
| spelling | doaj.art-3c65dddd321342099217a9f409bc354e2022-12-22T02:17:42ZengMDPI AGUniverse2218-19972020-02-01623310.3390/universe6020033universe6020033Squeezing of Primordial Gravitational Waves as Quantum DiscordAkira Matsumura0Yasusada Nambu1Department of Physics, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602, JapanDepartment of Physics, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602, JapanWe investigate the squeezing of primordial gravitational waves (PGWs) in terms of quantum discord. We construct a classical state of PGWs without quantum discord and compare it with the Bunch−Davies vacuum. Then it is shown that the oscillatory behavior of the angular-power spectrum of the cosmic microwave background (CMB) fluctuations induced by PGWs can be the signature of the quantum discord of PGWs. In addition, we discuss the effect of quantum decoherence on the entanglement and the quantum discord of PGWs for super-horizon modes. For the state of PGWs with decoherence effect, we examine the decoherence condition and the correlation condition introduced by C. Kiefer et al. (<i>Class. Quantum Grav.</i> <b>24</b> (2007) 1699). We show that the decoherence condition is not sufficient for the separability of PGWs and the correlation condition implies that the PGWs in the matter-dominated era have quantum discord.https://www.mdpi.com/2218-1997/6/2/33pgwssqueezingquantum discordoscillatory behaviordecoherence |
| spellingShingle | Akira Matsumura Yasusada Nambu Squeezing of Primordial Gravitational Waves as Quantum Discord Universe pgws squeezing quantum discord oscillatory behavior decoherence |
| title | Squeezing of Primordial Gravitational Waves as Quantum Discord |
| title_full | Squeezing of Primordial Gravitational Waves as Quantum Discord |
| title_fullStr | Squeezing of Primordial Gravitational Waves as Quantum Discord |
| title_full_unstemmed | Squeezing of Primordial Gravitational Waves as Quantum Discord |
| title_short | Squeezing of Primordial Gravitational Waves as Quantum Discord |
| title_sort | squeezing of primordial gravitational waves as quantum discord |
| topic | pgws squeezing quantum discord oscillatory behavior decoherence |
| url | https://www.mdpi.com/2218-1997/6/2/33 |
| work_keys_str_mv | AT akiramatsumura squeezingofprimordialgravitationalwavesasquantumdiscord AT yasusadanambu squeezingofprimordialgravitationalwavesasquantumdiscord |