Solid State Superatoms
Lead Research Organisation:
Durham University
Department Name: Physics
Abstract
The modern digital world relies on classical two-level systems - binary bits. A major theme of current physics research is the development of their quantum equivalent "qubits" - isolated two-level quantum systems, for applications in computing, sensing, measurement and communication. A logical quantum bit may be encoded using the physical states of an ensemble of many individual atoms. A powerful way to carry out such a collective encoding is to exploit highly excited electronic states, known as Rydberg states that have strong long-range interactions with neighbouring atoms. So far, this method has been demonstrated in a laser-cooled atomic gas, but not in the solid state.
We propose to use atom-like electronic states known as excitons, in a semiconducting signal. Excitons couple to light and can be excited to a Rydberg state, where their wavefunction can encapsulate billions of lattice sites. Using methods from solid state physics (strain engineering) and atomic physics (microwave control), we aim to isolate collective solid state two-level systems (superatoms), and prove their existence using the quantum properties of the light they emit. Finally we plan to exploit the translational symmetry of the bulk crystal environment to create tailored arrays of superatoms.
We propose to use atom-like electronic states known as excitons, in a semiconducting signal. Excitons couple to light and can be excited to a Rydberg state, where their wavefunction can encapsulate billions of lattice sites. Using methods from solid state physics (strain engineering) and atomic physics (microwave control), we aim to isolate collective solid state two-level systems (superatoms), and prove their existence using the quantum properties of the light they emit. Finally we plan to exploit the translational symmetry of the bulk crystal environment to create tailored arrays of superatoms.
Planned Impact
Short term: The primary beneficiary of the proposed work is the UK Quantum technology community (scientists, engineers and companies), in the following ways:
-People: The project will directly train two PDRAs in the cutting-edge skills needed in the quantum technology arena, and provide a training opportunity for at least two graduate students, as well as undergraduates.
-Knowledge: We open up a new research direction in the solid state that exploits atom-like highly excited states, with applications that include quantum optics and quantum interfaces. The proposal combines methods from solid state and atomic physics, with impact in both. We plan to use this project link these communities more closely.
Medium and long term: Economic impact could result in the medium to long term, through applications of the proposed research to sources of non-classical light and interfaces to superconducting quantum circuits such as those used in the first commercial quantum computer (D-Wave).
-People: The project will directly train two PDRAs in the cutting-edge skills needed in the quantum technology arena, and provide a training opportunity for at least two graduate students, as well as undergraduates.
-Knowledge: We open up a new research direction in the solid state that exploits atom-like highly excited states, with applications that include quantum optics and quantum interfaces. The proposal combines methods from solid state and atomic physics, with impact in both. We plan to use this project link these communities more closely.
Medium and long term: Economic impact could result in the medium to long term, through applications of the proposed research to sources of non-classical light and interfaces to superconducting quantum circuits such as those used in the first commercial quantum computer (D-Wave).
Publications
Adams C
(2020)
Rydberg atom quantum technologies
in Journal of Physics B: Atomic, Molecular and Optical Physics
Bai Z
(2020)
Self-Induced Transparency in Warm and Strongly Interacting Rydberg Gases.
in Physical review letters
Benhemou A
(2023)
Universality of Z 3 parafermions via edge-mode interaction and quantum simulation of topological space evolution with Rydberg atoms
in Physical Review Research
Gallagher L
(2022)
Microwave-optical coupling via Rydberg excitons in cuprous oxide
in Physical Review Research
Lynch S
(2021)
Rydberg excitons in synthetic cuprous oxide Cu 2 O
in Physical Review Materials
Ogden T
(2019)
Quasisimultons in Thermal Atomic Vapors
in Physical Review Letters
Pritchett J
(2024)
Giant microwave-optical Kerr nonlinearity via Rydberg excitons in cuprous oxide
in APL Photonics
Rogers J
(2022)
High-resolution nanosecond spectroscopy of even-parity Rydberg excitons in Cu 2 O
in Physical Review B
Description | We have discovered three things so far: 1. Electrons and holes can bind together in a semiconductor to form excitons, which are like hydrogen atoms. We have shown that just like real atoms, these excitons can couple strongly to microwave radiation that drives transitions between the excitonic energy levels. This could be used to couple light to microwave fields inside quantum computers. 2. Until now, naturally occurring crystals of the material we use (cuprous oxide) have performed better than synthetic ones. By measuring a wide range of parameters we have shown this is due to copper vacancies in the synthetic material, and we have shown that we can reduce their concentration using annealling. 3. Using a spectroscopy technique known as second harmonic generation, we were able to eliminate the background absorption of light due to phonons from our signals, potentially increasing our chances of seeing quantum light. |
Exploitation Route | In the longer term this work could be developed to couple together superconducting microwave circuits and light. DSTL may also choose to investigate possible applications |
Sectors | Digital/Communication/Information Technologies (including Software) |
URL | https://www.dur.ac.uk/qlm/research/rydbergsystems/ |
Description | Hybrid Quantum System of Excitons and Superconductors |
Amount | £637,700 (GBP) |
Funding ID | EP/X03853X/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 07/2023 |
End | 07/2027 |
Description | CASE studentship with DSTL |
Organisation | Defence Science & Technology Laboratory (DSTL) |
Country | United Kingdom |
Sector | Public |
PI Contribution | Working with DSTL exploring microwave sensing with excitons in cuprous oxide |
Collaborator Contribution | Partner for industrial CASE - stipend enhancement and hosting of placement |
Impact | This award helped support the two publications produced from the Solid State Superatoms grant, by part-funding the PhD of Liam Gallagher. These are https://journals.aps.org/prmaterials/abstract/10.1103/PhysRevMaterials.5.084602 and https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.4.013031 |
Start Year | 2017 |
Description | Durham/Cardiff collaboration on cuprous oxide |
Organisation | Cardiff University |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Leader of the consortium. Research on microwave/optical conversion |
Collaborator Contribution | expertise in solid-state physics, IR measurements, quantum optics |
Impact | https://doi.org/10.1063/5.0192710 https://doi.org/10.1103/PhysRevB.105.115206 https://doi.org/10.1103/PhysRevResearch.4.013031 https://doi.org/10.1103/PhysRevMaterials.5.084602 |
Start Year | 2014 |
Description | Celebrate Science 2019 |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Celebrate Science is an annual science festival aimed at school children held in Durham in the October half term. It is well established, and attended by >1000 people over typically four days. Staff employed on this project contributed to an activity on optics (polarization) and spectroscopy |
Year(s) Of Engagement Activity | 2019 |
URL | https://www.dur.ac.uk/celebrate.science/ |