---
_id: '12900'
abstract:
- lang: eng
text: "About a 100 years ago, we discovered that our universe is inherently noisy,
that is, measuring any physical quantity with a precision beyond a certain point
is not possible because of an omnipresent inherent noise. We call this - the quantum
noise. Certain physical processes allow this quantum noise to get correlated in
conjugate physical variables. These quantum correlations can be used to go beyond
the potential of our inherently noisy universe and obtain a quantum advantage
over the classical applications. \r\n\r\nQuantum noise being inherent also means
that, at the fundamental level, the physical quantities are not well defined and
therefore, objects can stay in multiple states at the same time. For example,
the position of a particle not being well defined means that the particle is in
multiple positions at the same time. About 4 decades ago, we started exploring
the possibility of using objects which can be in multiple states at the same time
to increase the dimensionality in computation. Thus, the field of quantum computing
was born. We discovered that using quantum entanglement, a property closely related
to quantum correlations, can be used to speed up computation of certain problems,
such as factorisation of large numbers, faster than any known classical algorithm.
Thus began the pursuit to make quantum computers a reality. \r\n\r\nTill date,
we have explored quantum control over many physical systems including photons,
spins, atoms, ions and even simple circuits made up of superconducting material.
However, there persists one ubiquitous theme. The more readily a system interacts
with an external field or matter, the more easily we can control it. But this
also means that such a system can easily interact with a noisy environment and
quickly lose its coherence. Consequently, such systems like electron spins need
to be protected from the environment to ensure the longevity of their coherence.
Other systems like nuclear spins are naturally protected as they do not interact
easily with the environment. But, due to the same reason, it is harder to interact
with such systems. \r\n\r\nAfter decades of experimentation with various systems,
we are convinced that no one type of quantum system would be the best for all
the quantum applications. We would need hybrid systems which are all interconnected
- much like the current internet where all sorts of devices can all talk to each
other - but now for quantum devices. A quantum internet. \r\n\r\nOptical photons
are the best contenders to carry information for the quantum internet. They can
carry quantum information cheaply and without much loss - the same reasons which
has made them the backbone of our current internet. Following this direction,
many systems, like trapped ions, have already demonstrated successful quantum
links over a large distances using optical photons. However, some of the most
promising contenders for quantum computing which are based on microwave frequencies
have been left behind. This is because high energy optical photons can adversely
affect fragile low-energy microwave systems. \r\n\r\nIn this thesis, we present
substantial progress on this missing quantum link between microwave and optics
using electrooptical nonlinearities in lithium niobate. The nonlinearities are
enhanced by using resonant cavities for all the involved modes leading to observation
of strong direct coupling between optical and microwave frequencies. With this
strong coupling we are not only able to achieve almost 100\\% internal conversion
efficiency with low added noise, thus presenting a quantum-enabled transducer,
but also we are able to observe novel effects such as cooling of a microwave mode
using optics. The strong coupling regime also leads to direct observation of dynamical
backaction effect between microwave and optical frequencies which are studied
in detail here. Finally, we also report first observation of microwave-optics
entanglement in form of two-mode squeezed vacuum squeezed 0.7dB below vacuum level.
\r\nWith this new bridge between microwave and optics, the microwave-based quantum
technologies can finally be a part of a quantum network which is based on optical
photons - putting us one step closer to a future with quantum internet. "
acknowledged_ssus:
- _id: M-Shop
- _id: SSU
- _id: NanoFab
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Rishabh
full_name: Sahu, Rishabh
id: 47D26E34-F248-11E8-B48F-1D18A9856A87
last_name: Sahu
orcid: 0000-0001-6264-2162
citation:
ama: Sahu R. Cavity quantum electrooptics. 2023. doi:10.15479/at:ista:12900
apa: Sahu, R. (2023). Cavity quantum electrooptics. Institute of Science
and Technology Austria. https://doi.org/10.15479/at:ista:12900
chicago: Sahu, Rishabh. “Cavity Quantum Electrooptics.” Institute of Science and
Technology Austria, 2023. https://doi.org/10.15479/at:ista:12900.
ieee: R. Sahu, “Cavity quantum electrooptics,” Institute of Science and Technology
Austria, 2023.
ista: Sahu R. 2023. Cavity quantum electrooptics. Institute of Science and Technology
Austria.
mla: Sahu, Rishabh. Cavity Quantum Electrooptics. Institute of Science and
Technology Austria, 2023, doi:10.15479/at:ista:12900.
short: R. Sahu, Cavity Quantum Electrooptics, Institute of Science and Technology
Austria, 2023.
date_created: 2023-05-05T11:08:50Z
date_published: 2023-05-05T00:00:00Z
date_updated: 2023-08-24T11:16:35Z
day: '05'
ddc:
- '537'
- '535'
- '539'
degree_awarded: PhD
department:
- _id: GradSch
- _id: JoFi
doi: 10.15479/at:ista:12900
ec_funded: 1
file:
- access_level: closed
checksum: 8cbdab9c37ee55e591092a6f66b272c4
content_type: application/x-zip-compressed
creator: rsahu
date_created: 2023-05-09T08:45:14Z
date_updated: 2023-06-06T22:30:03Z
embargo_to: open_access
file_id: '12928'
file_name: thesis.zip
file_size: 36767177
relation: source_file
- access_level: closed
checksum: 439659ead46618147309be39d9dd5a8c
content_type: application/pdf
creator: rsahu
date_created: 2023-05-09T08:51:17Z
date_updated: 2023-07-06T11:37:40Z
file_id: '12929'
file_name: thesis_pdfa_final.pdf
file_size: 17501990
relation: main_file
file_date_updated: 2023-07-06T11:37:40Z
has_accepted_license: '1'
keyword:
- quantum optics
- electrooptics
- quantum networks
- quantum communication
- transduction
language:
- iso: eng
license: https://creativecommons.org/licenses/by-nc-sa/4.0/
month: '05'
oa_version: Published Version
page: '190'
project:
- _id: 26336814-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '758053'
name: A Fiber Optic Transceiver for Superconducting Qubits
- _id: 9B868D20-BA93-11EA-9121-9846C619BF3A
call_identifier: H2020
grant_number: '899354'
name: Quantum Local Area Networks with Superconducting Qubits
- _id: bdb108fd-d553-11ed-ba76-83dc74a9864f
name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration
of Superconducting Quantum Circuits
publication_identifier:
isbn:
- 978-3-99078-030-5
issn:
- 2663 - 337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '13175'
relation: new_edition
status: public
- id: '10924'
relation: part_of_dissertation
status: public
- id: '9114'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Johannes M
full_name: Fink, Johannes M
id: 4B591CBA-F248-11E8-B48F-1D18A9856A87
last_name: Fink
orcid: 0000-0001-8112-028X
title: Cavity quantum electrooptics
tmp:
image: /images/cc_by_nc_sa.png
legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode
name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC
BY-NC-SA 4.0)
short: CC BY-NC-SA (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...