William T. Buttler

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Quantum cryptography was introduced in the mid1980s [1] as a new method for generating the shared, secret random number sequences, or cryptographic keys, that are used in crypto-systems to provide communications security. The appeal of quantum cryptography is that its security is based on laws of Nature, in contrast to existing methods of key distribution(More)
The secure distribution of the secret random bit sequences known as “key” material, is an essential precursor to their use for the encryption and decryption of confidential communications. Quantum cryptography is an emerging technology for secure key distribution with single-photon transmissions: Heisenberg’s uncertainty principle ensures that an adversary(More)
The hydrodynamic operation of the "Forest Flyer" type of explosive launching system for shock physics projectiles was investigated in detail using one and two dimensional continuum dynamics simulations. The simulations were numerically converged and insensitive to uncertainties in the material properties; they reproduced the speed of the projectile and the(More)
We present a new fiber based quantum key distribution (QKD) scheme which can be regarded as a modification of an idea proposed by Inoue, Waks and Yamamoto (IWY) [1]. The scheme described here uses a single phase modulator and two differential delay elements in series at the transmitter that form an interferometer when combined with a third differential(More)
A general analysis of thermal noise in torsion pendulums is presented. The specific case where the torsion angle is kept fixed by electronic feedback is analyzed. This analysis is applied to a recent experiment that employed a torsion pendulum to measure the Casimir force. The ultimate limit to the distance at which the Casimir force can be measured to high(More)
We use the Richtmyer-Meshkov instability (RMI) at a metal-gas interface to infer the metal's yield stress (Y) under shock loading and release. We first model how Y stabilizes the RMI using hydrodynamics simulations with a perfectly plastic constitutive relation for copper (Cu). The model is then tested with molecular dynamics (MD) of crystalline Cu by(More)
We formalize the physics of an optical heterodyne accelerometer that allows measurement of low and high velocities from material surfaces under high strain. The proposed apparatus incorporates currently common optical velocimetry techniques used in shock physics, with interferometric techniques developed to self-stabilize and passively balance(More)