{"id":{"repo_id":"mit","oai_identifier":"oai:dspace.mit.edu:1721.1/150692"},"canonical_url":"https://search.dev.ndltd.org/etd/mit/oai:dspace.mit.edu:1721.1/150692","repository":{"repo_id":"mit","name":"MIT","base_url":"https://dspace.mit.edu/oai/request"},"display":{"title":"Quantum Controlled Collisions and Magnetic Trapping of Ultracold NaLi Molecules","abstract":"²³Na⁶Li is a fermionic molecule that has weak singlet-triplet mixing, making it a suitable system to study the triplet rovibrational ground state (𝑎³Σ⁺, 𝑣 = 0,𝑁 = 0). It is notable for its both non-zero electric (0.175 Debye) and magnetic (2𝜇𝐵) dipole moments and small two-body scattering rate, as predicted by the universal model for cold collision. Additionally, ²³Na⁶Li is the lightest bi-alkali molecule, and the theoretical simulation of collisions is relatively feasible compared to other heavy molecules which makes it a promising benchmark system for theoretical quantum scattering calculations. This thesis describes three experiments and a numerical/theoretical work on ²³Na⁶Li molecules in the triplet ground state. The first two experiments are on molecular Feshbach resonances: in spin-polarized ²³Na⁶Li+²³Na collisions and in ²³Na⁶Li+²³Na⁶Li collisions. The first experiment focuses on the spectroscopic study of Feshbach resonances in two possible spin-polarized ²³Na⁶Li+²³Na collisions from near 0 to 1400 Gauss. This allows learning about the molecular interaction potential surface and intermediate collision complexes, benchmarking theory, and controlling reactive collisions. The second experiment is a report of an unpredicted 𝑝-wave Feshbach resonance in ²³Na⁶Li+²³Na⁶Li collisions and interpretations. The resonance occurs for molecules in the lower stretched hyperfine state near an open-channel degeneracy. The collision loss rate is enhanced by more than two orders of magnitude from the 𝑝-wave universal value at the background to near the 2D unitarity limit. In addition to the search for magnetically tunable resonances, ²³Na⁶Li molecules in the triplet potential are suitable for magnetic trapping. The third experiment describes building an improved experimental setup that allows magnetic trapping of ²³Na⁶Li molecules and studying various collisions in the magnetic trap by quantum state control of molecules and atoms. The molecular density is a factor of 10⁵ higher than that reported for magnetically trapped ultracold molecules, and the temperature is ≈ 1𝜇𝐾. This condition enables observation of both atom-molecule and molecule-molecule collisions in the ultracold regime and sympathetic cooling of ²³Na⁶Li by evaporative cooling of ²³Na in the magnetic trap. Lastly, this thesis presents the numerical and theoretical approach to finding a window for an all-optical creation of molecules using Raman transitions from ²³Na and ⁶Li atoms to ²³Na⁶Li molecules. All-optical creation of molecules in which the magnetic association step near a Feshbach resonance is eliminated is expected to broaden the horizon of ultracold molecules to a larger pool and to eliminate the need for high magnetic fields.","abstract_html":"²³Na⁶Li is a fermionic molecule that has weak singlet-triplet mixing, making it a suitable system to study the triplet rovibrational ground state (𝑎³Σ⁺, 𝑣 = 0,𝑁 = 0). It is notable for its both non-zero electric (0.175 Debye) and magnetic (2𝜇𝐵) dipole moments and small two-body scattering rate, as predicted by the universal model for cold collision. Additionally, ²³Na⁶Li is the lightest bi-alkali molecule, and the theoretical simulation of collisions is relatively feasible compared to other heavy molecules which makes it a promising benchmark system for theoretical quantum scattering calculations. This thesis describes three experiments and a numerical/theoretical work on ²³Na⁶Li molecules in the triplet ground state. The first two experiments are on molecular Feshbach resonances: in spin-polarized ²³Na⁶Li+²³Na collisions and in ²³Na⁶Li+²³Na⁶Li collisions. The first experiment focuses on the spectroscopic study of Feshbach resonances in two possible spin-polarized ²³Na⁶Li+²³Na collisions from near 0 to 1400 Gauss. This allows learning about the molecular interaction potential surface and intermediate collision complexes, benchmarking theory, and controlling reactive collisions. The second experiment is a report of an unpredicted 𝑝-wave Feshbach resonance in ²³Na⁶Li+²³Na⁶Li collisions and interpretations. The resonance occurs for molecules in the lower stretched hyperfine state near an open-channel degeneracy. The collision loss rate is enhanced by more than two orders of magnitude from the 𝑝-wave universal value at the background to near the 2D unitarity limit. In addition to the search for magnetically tunable resonances, ²³Na⁶Li molecules in the triplet potential are suitable for magnetic trapping. The third experiment describes building an improved experimental setup that allows magnetic trapping of ²³Na⁶Li molecules and studying various collisions in the magnetic trap by quantum state control of molecules and atoms. The molecular density is a factor of 10⁵ higher than that reported for magnetically trapped ultracold molecules, and the temperature is ≈ 1𝜇𝐾. This condition enables observation of both atom-molecule and molecule-molecule collisions in the ultracold regime and sympathetic cooling of ²³Na⁶Li by evaporative cooling of ²³Na in the magnetic trap. Lastly, this thesis presents the numerical and theoretical approach to finding a window for an all-optical creation of molecules using Raman transitions from ²³Na and ⁶Li atoms to ²³Na⁶Li molecules. All-optical creation of molecules in which the magnetic association step near a Feshbach resonance is eliminated is expected to broaden the horizon of ultracold molecules to a larger pool and to eliminate the need for high magnetic fields.","abstract_has_math":false,"creators":["Park, Juliana"],"institution":"Massachusetts Institute of Technology","degree_name":"Doctoral","degree_level":null,"degree_discipline":null,"degree_department":"Massachusetts Institute of Technology. Department of Physics","school":null,"contributors":[],"advisors":["Ketterle, Wolfgang"],"committee_chairs":[],"committee_members":[],"year":2023,"date_issued":"2023-02","date_published":"2023-02","updated_at":"2026-07-22T22:22:29Z","subjects":[],"languages":[],"rights":["In Copyright - Educational Use Permitted","Copyright MIT"],"rights_urls":["http://rightsstatements.org/page/InC-EDU/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/1721.1/150692","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Ketterle, Wolfgang"]},{"key":"dc:contributor.department","label":"Department","values":["Massachusetts Institute of Technology. Department of Physics"]},{"key":"dc:creator","label":"Author","values":["Park, Juliana"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2023-05-15T19:32:48Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2023-05-15T19:32:48Z"]},{"key":"dc:date.issued","label":"Date","values":["2023-02"]},{"key":"dc:publisher","label":"Institution","values":["Massachusetts Institute of Technology"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctoral","Doctor of Philosophy"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright - Educational Use Permitted","Copyright MIT"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/page/InC-EDU/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/1721.1/150692"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["²³Na⁶Li is a fermionic molecule that has weak singlet-triplet mixing, making it a suitable system to study the triplet rovibrational ground state (𝑎³Σ⁺, 𝑣 = 0,𝑁 = 0). It is notable for its both non-zero electric (0.175 Debye) and magnetic (2𝜇𝐵) dipole moments and small two-body scattering rate, as predicted by the universal model for cold collision. Additionally, ²³Na⁶Li is the lightest bi-alkali molecule, and the theoretical simulation of collisions is relatively feasible compared to other heavy molecules which makes it a promising benchmark system for theoretical quantum scattering calculations. This thesis describes three experiments and a numerical/theoretical work on ²³Na⁶Li molecules in the triplet ground state. The first two experiments are on molecular Feshbach resonances: in spin-polarized ²³Na⁶Li+²³Na collisions and in ²³Na⁶Li+²³Na⁶Li collisions. The first experiment focuses on the spectroscopic study of Feshbach resonances in two possible spin-polarized ²³Na⁶Li+²³Na collisions from near 0 to 1400 Gauss. This allows learning about the molecular interaction potential surface and intermediate collision complexes, benchmarking theory, and controlling reactive collisions. The second experiment is a report of an unpredicted 𝑝-wave Feshbach resonance in ²³Na⁶Li+²³Na⁶Li collisions and interpretations. The resonance occurs for molecules in the lower stretched hyperfine state near an open-channel degeneracy. The collision loss rate is enhanced by more than two orders of magnitude from the 𝑝-wave universal value at the background to near the 2D unitarity limit. In addition to the search for magnetically tunable resonances, ²³Na⁶Li molecules in the triplet potential are suitable for magnetic trapping. The third experiment describes building an improved experimental setup that allows magnetic trapping of ²³Na⁶Li molecules and studying various collisions in the magnetic trap by quantum state control of molecules and atoms. The molecular density is a factor of 10⁵ higher than that reported for magnetically trapped ultracold molecules, and the temperature is ≈ 1𝜇𝐾. This condition enables observation of both atom-molecule and molecule-molecule collisions in the ultracold regime and sympathetic cooling of ²³Na⁶Li by evaporative cooling of ²³Na in the magnetic trap. Lastly, this thesis presents the numerical and theoretical approach to finding a window for an all-optical creation of molecules using Raman transitions from ²³Na and ⁶Li atoms to ²³Na⁶Li molecules. All-optical creation of molecules in which the magnetic association step near a Feshbach resonance is eliminated is expected to broaden the horizon of ultracold molecules to a larger pool and to eliminate the need for high magnetic fields."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Ph.D."]},{"key":"dc:title","label":"Title","values":["Quantum Controlled Collisions and Magnetic Trapping of Ultracold NaLi Molecules"]}]}],"canonical_facts":{"dc:contributor.advisor":["Ketterle, Wolfgang"],"dc:contributor.department":["Massachusetts Institute of Technology. Department of Physics"],"dc:creator":["Park, Juliana"],"dc:date.accessioned":["2023-05-15T19:32:48Z"],"dc:date.available":["2023-05-15T19:32:48Z"],"dc:date.issued":["2023-02"],"dc:description.abstract":["²³Na⁶Li is a fermionic molecule that has weak singlet-triplet mixing, making it a suitable system to study the triplet rovibrational ground state (𝑎³Σ⁺, 𝑣 = 0,𝑁 = 0). It is notable for its both non-zero electric (0.175 Debye) and magnetic (2𝜇𝐵) dipole moments and small two-body scattering rate, as predicted by the universal model for cold collision. Additionally, ²³Na⁶Li is the lightest bi-alkali molecule, and the theoretical simulation of collisions is relatively feasible compared to other heavy molecules which makes it a promising benchmark system for theoretical quantum scattering calculations. This thesis describes three experiments and a numerical/theoretical work on ²³Na⁶Li molecules in the triplet ground state. The first two experiments are on molecular Feshbach resonances: in spin-polarized ²³Na⁶Li+²³Na collisions and in ²³Na⁶Li+²³Na⁶Li collisions. The first experiment focuses on the spectroscopic study of Feshbach resonances in two possible spin-polarized ²³Na⁶Li+²³Na collisions from near 0 to 1400 Gauss. This allows learning about the molecular interaction potential surface and intermediate collision complexes, benchmarking theory, and controlling reactive collisions. The second experiment is a report of an unpredicted 𝑝-wave Feshbach resonance in ²³Na⁶Li+²³Na⁶Li collisions and interpretations. The resonance occurs for molecules in the lower stretched hyperfine state near an open-channel degeneracy. The collision loss rate is enhanced by more than two orders of magnitude from the 𝑝-wave universal value at the background to near the 2D unitarity limit. In addition to the search for magnetically tunable resonances, ²³Na⁶Li molecules in the triplet potential are suitable for magnetic trapping. The third experiment describes building an improved experimental setup that allows magnetic trapping of ²³Na⁶Li molecules and studying various collisions in the magnetic trap by quantum state control of molecules and atoms. The molecular density is a factor of 10⁵ higher than that reported for magnetically trapped ultracold molecules, and the temperature is ≈ 1𝜇𝐾. This condition enables observation of both atom-molecule and molecule-molecule collisions in the ultracold regime and sympathetic cooling of ²³Na⁶Li by evaporative cooling of ²³Na in the magnetic trap. Lastly, this thesis presents the numerical and theoretical approach to finding a window for an all-optical creation of molecules using Raman transitions from ²³Na and ⁶Li atoms to ²³Na⁶Li molecules. All-optical creation of molecules in which the magnetic association step near a Feshbach resonance is eliminated is expected to broaden the horizon of ultracold molecules to a larger pool and to eliminate the need for high magnetic fields."],"dc:description.degree":["Ph.D."],"dc:identifier.uri":["https://hdl.handle.net/1721.1/150692"],"dc:publisher":["Massachusetts Institute of Technology"],"dc:rights":["In Copyright - Educational Use Permitted","Copyright MIT"],"dc:rights.uri":["http://rightsstatements.org/page/InC-EDU/1.0/"],"dc:title":["Quantum Controlled Collisions and Magnetic Trapping of Ultracold NaLi Molecules"],"dc:type":["Thesis"],"thesis:degree_name":["Doctoral","Doctor of Philosophy"]},"updated_at":"2026-07-22T22:22:29Z"}