Cryogenic Design and Performance of an Apparatus for Magnetically Trapping Ultracold Neutrons

Truman Wilson, Wei‐Ting Chen, Jacob Roberts

G. P. Berman, V. N. Gorshkov, V. I. Tsifrinovich

Brandl, MF, van Mourik, MW, Postler, L +15 more

We report on the design of a cryogenic setup for trapped ion quantum computing containing a segmented surface electrode trap. The heat shield of our cryostat is designed to attenuate alternating magnetic field noise, resulting in 120 dB reduction of 50 Hz noise along the magnetic field axis. We combine this efficient magnetic shielding with high optical access required for single ion addressing as well as for efficient state detection by placing two lenses each with numerical aperture 0.23 inside the inner heat shield. The cryostat design incorporates vibration isolation to avoid decoherence of optical qubits due to the motion of the cryostat. We measure vibrations of the cryostat of less than ±20 nm over 2 s. In addition to the cryogenic apparatus, we describe the setup required for an operation with 40Ca+ and 88Sr+ ions. The instability of the laser manipulating the optical qubits in 40Ca+ is characterized by yielding a minimum of its Allan deviation of 2.4 ⋅ 10-15 at 0.33 s. To evaluate the performance of the apparatus, we trapped 40Ca+ ions, obtaining a heating rate of 2.14(16) phonons/s and a Gaussian decay of the Ramsey contrast with a 1/e-time of 18.2(8) ms.

M. F. Brandl, M. W. van Mourik, L. Postler +15 more

We report on the design of a cryogenic setup for trapped ion quantum computing containing a segmented surface electrode trap. The heat shield of our cryostat is designed to attenuate alternating magnetic field noise, resulting in 120 dB reduction of 50 Hz noise along the magnetic field axis. We combine this efficient magnetic shielding with high optical access required for single ion addressing as well as for efficient state detection by placing two lenses each with numerical aperture 0.23 inside the inner heat shield. The cryostat design incorporates vibration isolation to avoid decoherence of optical qubits due to the motion of the cryostat. We measure vibrations of the cryostat of less than ±20 nm over 2 s. In addition to the cryogenic apparatus, we describe the setup required for an operation with 40Ca+ and 88Sr+ ions. The instability of the laser manipulating the optical qubits in 40Ca+ is characterized by yielding a minimum of its Allan deviation of 2.4 ⋅ 10−15 at 0.33 s. To evaluate the performance of the apparatus, we trapped 40Ca+ ions, obtaining a heating rate of 2.14(16) phonons/s and a Gaussian decay of the Ramsey contrast with a 1/e-time of 18.2(8) ms.

Yu. G. Abov, V. V. Vladimirsky, V.K. Rissukhin +4 more

Cold atom apparatuses have proven to be an invaluable tool in quantum many-body studies as they provide a platform for quantum simulations. These systems allow us to explore thousands of avenues related to neutron stars, novel technologies, quantum many-body physics and many more. Since joining the Sommer Laboratory group, I have made significant contribution to the design and construction of an ultracold 6Li apparatus. In this work I describe the design of a 'two-part' vacuum system for the injection and manipulation of lithium atoms. Additionally, I describe the lasersystems necessary to cool and capture hot lithium atoms to temperatures on the order of several hundred micro-kelvin. Finally I discuss the design and performance of our built apparatus at the time of this dissertation's submission. I will also give a brief overview of research that has led up to this point in the field of atomic physics followed by a description of our atomic apparatus and the future application of this apparatus.