All They Want Is to Gain Attention : Press Coverage and the Selma-to-Montgomery March

March in Alabama can be a beautiful month with warm days, cool nights, flowers bursting from the ground with vibrant yellows, reds, and violets, and greens everywhere. Jonquils push through the ground like horns resounding with the song of spring and forsythia adorns itself ingold.1 March can also fulfill the proverb “comes in like a lion, goes out like a lamb.” Alabama’s March of 1965 offered cold, wet, windy weather up until the end. But a different wind blew through Selma that month—the wind of discontent and change. For the first three months of 1965, Dr. Martin Luther King, Jr.’s Southern Christian Leadership Conference (SCLC), had conducted a voter registration drive in central Alabama’s Black Belt counties. King sought to expose voting barriers in this part of the South as a means of eliminating them nation-wide through federal legislation.2 Press coverage would be vital, focusing attention on the problem he sought to correct. Settlers originally called the counties bordering the Alabama River the Black Belt because the rich limestone soil had become dark loam through the centuries. But the name also assumed an ethnological meaning; a majority of inhabitants descended from slaves who once worked its antebellum plantations. In 1965, those land-holdings still dotted the countryside, and many features of the old order still flourished. Contrasts also marked the region: majestic homes and ramshackle shanties, opulence and poverty, white and black, played against the endless sweep of cotton fields. In the midst of this Black Belt, athwart the Alabama River, sat Dallas County. Selma, on the river’s north bank almost in the center of both county and state, served as the county seat.

Accelerated Randomized Benchmarking

Quantum information processing offers promising advances for a wide range of fields and applications, provided that we can efficiently assess the performance of the control applied in candidate systems. That is, we must be able to determine whether we have implemented a desired gate, and refine accordingly. Randomized benchmarking reduces the difficulty of this task by exploiting symmetries in quantum operations. Here, we bound the resources required for benchmarking and show that, with prior information, we can achieve several orders of magnitude better accuracy than in traditional approaches to benchmarking. Moreover, by building on state-of-the-art classical algorithms, we reach these accuracies with near-optimal resources. Our approach requires an order of magnitude less data to achieve the same accuracies and to provide online estimates of the errors in the reported fidelities. We also show that our approach is useful for physical devices by comparing to simulations. Our results thus enable the application of randomized benchmarking in new regimes, and dramatically reduce the experimental effort required to assess control fidelities in quantum systems. Finally, our work is based on open-source scientific libraries, and can readily be applied in systems of interest.Comment: 10 pages, full source code at https://github.com/cgranade/accelerated-randomized-benchmarking #quantuminfo #benchmarkin

Second Monday in Advent Zechariah 9:9-10

I love snow; it forms the core of my earliest recollections. My father finished seminary at Louisville during my first years. Of that time I “remember” only three incidents; two involve snow. One is a travel story, of our motoring north from Alabama through the snow until, exhausted and trapped, we stopped for the night. Since that story is family legend, the memory may involve the telling rather than the experience. The other is too firmly etched, drawing as it does on sensory perceptions which cannot be a storyteller’s creation, even in someone with as active an imagination as mine