Quantum Information Science with Ultracold Laser-cooled Molecules
Abstract
Ultracold molecules are a new research platform for quantum information processing. Establishing full control over the quantum states of ultracold molecules is a necessary step towards using molecules for quantum computation, quantum networking, quantum simulation, quantum sensing and ultra-precise clocks. Molecules contain several diverse structures, including rotational and vibrational, that can enhance quantum applications. Under this project we will develop techniques required to implement high-fidelity quantum state control of three major classes of molecules- diatomic, linear polyatomic and asymmetric tops. Each of these molecular structures has its own unique advantages for quantum science applications. We will pursue three related projects with molecules that are brought to the ultracold regime (<100 microK) via direct laser cooling techniques, pioneered in our research group. In the diatomic molecule project, we have already trapped individual CaF molecules in an array of optical tweezers and demonstrated quantum gates mediated by dipole-dipole interactions between molecules in adjacent tweezers. We will now improve the fidelity of these gates by implementing cooling to the motional ground state of the tweezer traps and making upgrades that will allow the tweezer traps to be moved closer together, thereby increasing interaction strengths and decreasing gate times, creating a more powerful quantum platform. We also plan to upgrade to a two-dimensional tweezer array, increasing the number of molecules that can be simultaneously controlled, which will increase the size and power of our quantum computer. In the two other projects, we will use polyatomic molecules which possess, as compared to diatomic molecules, an even greater wealth of quantum states and structural features that are predicted to be advantageous for quantum science applications. Using equipment funded by this grant we will initially laser cool two species of polyatomic molecules. In the asymmetric top molecule (ATM) project, we will first form a magneto-optical trap of CaSH molecules and then cool them to microkelvin temperatures and load them into optical tweezers. We will then demonstrate coherent control over the internal states of CaSH molecules in optical tweezers, aiming to couple them as qubits in an array, thus providing the key step towards universal quantum computation (with enhanced error correction) with ATMs. In the linear polyatomic molecule project, we will pursue high-fidelity coherent control of SrOH molecules in an excited vibrational state that is easily polarized in external electric fields. Specifically, we plan to build a vacuum chamber with pristine shielding from external magnetic and electric fields and implement transport of laser-cooled SrOH molecules from the initial cooling and trapping chamber into the new vacuum cell, which is optimized for the external field control required for high-fidelity quantum gates. We will then load SrOH into optical tweezers and demonstrate coherent optical and microwave state control, as well as high-fidelity readout techniques and qubit coupling. With each of these systems we will test quantum computation and simulation protocols, each best suited to the advantages of these new platforms, thus extending the frontier of quantum information science.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 05, 2025
- Source ID
- FA95502410060
Entities
People
- John M. Doyle
Organizations
- Air Force Office of Scientific Research
- President and Fellows of Harvard College
- United States Air Force