Papers by nathan lachenmyer
This research group seeks to understand and develop the experimental and theoretical potential fo... more This research group seeks to understand and develop the experimental and theoretical potential for information processing and communications using the laws of quantum physics. Two fundamental questions motivate our work: (1) How can a large-scale, reliable quantum computer be realized? (2) What new algorithms, cryptographic primitives, and metrology techniques are enabled by quantum information? The first question is primarily experimental. We intend to build a large-scale, reliable quantum computer over the next few decades. Based on our successes with realizing small quantum computers, and after three years of testing, modeling, and planning, we have come to understand how this can be achieved by combining fault tolerance techniques developed by von Neumann, with methods from atomic physics.
Proceedings of the ACM on Computer Graphics and Interactive Techniques
This paper describes the public art installation In Love With The World by artist Anicka Yi, whic... more This paper describes the public art installation In Love With The World by artist Anicka Yi, which embodies a complex virtual ecosystem of autonomous agents in a physical space. The agents, called Aerobes, are inspired by the lifecycle of the Aurelia sp. jellyfish, and use artificial life techniques designed by the authors to simulate the behavior of two distinct phenotypes. These agents are embodied in the Tate Modern's Turbine Hall using lighter-than-air soft robotics utilizing helium that can respond to museum visitors through sensors embedded in the space. By creating organic-looking fully autonomous agents that are capable of real-time interaction, we hope to create an experience that causes viewers to question what living with machines might feel like in a speculative far-future, and to imagine an alternative form of artificial intelligence that is neither threatening to humanity nor subservient to it, but exists in an altogether parallel track as a new form of life.
Special Interest Group on Computer Graphics and Interactive Techniques Conference Talks
The author hereby grants to MIT permission to reproduce and distribute publicly paper and electro... more The author hereby grants to MIT permission to reproduce and distribute publicly paper and electronic copies of this thesis document in whole or in part. Abstract Neurons serve as the basic unit of computation within the nervous system. As the nervous system is involved with the encoding, transmission, processing, and decoding of information at every level, characterization of the nervous system is of the utmost interest to neuroscience. However, techniques for probing the nervous system have previously focused primarily of characterizing single cell behavior, which does not provide insight as to the functioning of the system as a whole. This is further complicated by the fact that functional network of neurons are typically spatial interwoven, rendering spatially-limited stimulation techniques ineffective. The desire to characterize the system in its entirety necessitates the development of neuronal probes that can target functional subpopulations of cells. A proposed system for suc...
Journal of Applied Physics, 2011
Electrical charging of metal surfaces due to photoelectric generation of carriers is of concern i... more Electrical charging of metal surfaces due to photoelectric generation of carriers is of concern in trapped ion quantum computation systems, due to the high sensitivity of the ions' motional quantum states to deformation of the trapping potential. The charging induced by typical laser frequencies involved in Doppler cooling and quantum control is studied here, with microfabricated surface-electrode traps made of aluminum, copper, and gold, operated at 6 K with a single Sr þ ion trapped 100 lm above the trap surface. The lasers used are at 370, 405, 460, and 674 nm, and the typical photon flux at the trap is 10 14 photons/cm 2 /sec. Charging is detected by monitoring the ion's micromotion signal, which is related to the number of charges created on the trap. A wavelength and material dependence of the charging behavior is observed: Lasers at lower wavelengths cause more charging, and aluminum exhibits more charging than copper or gold. We describe the charging dynamic based on a rate-equation approach. V
Ion traps provide an excellent tool for controlling and observing the state of a single trapped i... more Ion traps provide an excellent tool for controlling and observing the state of a single trapped ion. For this reason, ion traps have been proposed as a possible system for large-scale quantum computation. However, many obstacles must be overcome before quantum computing can become a reality. In particular, perturbations in the electric field due to noise and electrode charging must be reduced to increase coherence of the motional quantum state. Gold has been a popular choice in the past due to its inert properties; however, it is undesireable due its incompatibility with CMOS technology. This has led to increased research into alternative CMOS-compatible materials, such as aluminum and copper. This thesis presents measurements of electric field noise and light-induced charging in aluminum, copper, and gold surface electrode traps. In addition, the effect of oxide growth on field noise and electrode charging is explored by controlling the thickness of aluminum oxide on several aluminum traps. The measurements show that electric field noise can be suppressed in aluminum traps to approximately 10-18 V 2 cm-2 Hz-1, matching the noise exhibited in gold traps, and that copper traps exhibit noise within an order of magnitude of that in aluminum and gold. However, the natural oxide of aluminum poses many problems towards high-performance aluminum ion traps. The electric field noise is shown to be strongly dependent on the oxide thickness, increasing the noise by a factor of about 10 until saturation at a thickness of 13 nm. Charging of surface electrodes is shown to be highly dependent upon the material, but the model presented does not match the experimental data and is found to be incomplete. These results indicate that ion traps made out of CMOS-compatible materials can perform as well as more traditional traps fabricated from gold with respect to heating and charging as long as methods are developed for controlling oxide growth.
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Papers by nathan lachenmyer