| Energy-Momentum Tensor for the Electromagnetic Field in a Dielectric |
30 Jun 2010 |
7 pages |
| Authors:
Michael E Crenshaw; Thomas B Bahder; ARMY AVIATION AND MISSILE COMMAND REDSTONE ARSENAL AL MISSILE RESEARCH DEVELOPMENT AND ENGINEERING CENTER
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 | The total momentum of a thermodynamically closed system is unique, as is the total energy. Nevertheless, there is continuing confusion concerning the correct form of the momentum and the energy-momentum tensor for an electromagnetic field interacting with a linear dielectric medium. Here we investigate the energy and momentum in a closed system composed of a propagating electromagnetic field and a negligibly reflecting dielectric. The Gordon momentum is easily identified as ... |
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| The Effectiveness of Quantum Operations for Eavesdropping on Sealed Messages |
04 Apr 2007 |
11 pages |
| Authors:
Paul A Lopata; Thomas B Bahder; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| A quantum protocol is described which enables a user to send sealed messages and that allows for the detection of active eavesdroppers. We examine a class of eavesdropping strategies, those that make use of quantum operations, and we determine the information gain versus disturbance caused by these strategies. We demonstrate this tradeoff with an example and we compare this protocol to quantum key distribution, quantum direct communication, and quantum seal ... |
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| Phase Sensitivity of a Mach-Zehnder Quantum Sensor |
31 Jan 2007 |
5 pages |
| Authors:
Thomas B Bahder; Paul A Lopata; ARMY AVIATION AND MISSILE RESEARCH DEVELOPMENT AND ENG CTR REDSTONE ARSENAL AL
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| We investigate the dependence of the fidelity of a Mach-Zehnder quantum interferometer on the prior information about the phase, for Fock state input and for maximally entangled (N00N) state input. For no prior information, the fidelity for Fock state input is greater than for N00N state input. In the limit of a narrow dis- tribution describing the prior information, we find that both Fock and N00N state inputs lead to ... |
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| Sending Sensitive Messages in Quantum Packages |
02 Jun 2006 |
5 pages |
| Authors:
Paul A Lopata; Thomas B Bahder; ARMY RESEARCH LAB ADELPHI MD
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| A communication protocol is introduced that allows the receiver of a message to place an a posteriori bound on the amount of information that an eavesdropper could have obtained during transmission of that message. This quantum cryptographic protocol is distinct from quantum key distribution. The quantum states and measurements required by this protocol are simple enough that it can be implemented using existing technology. |
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| Quantum Positioning System |
Dec 2004 |
25 pages |
| Authors:
Thomas B Bahder; ARMY RESEARCH LAB ADELPHI MD
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| A quantum positioning system (QPS) is proposed that can provide a user with all four of his space-time coordinates. The user must carry a corner cube reflector, a good clock, and have a two-way classical channel of communication with the origin of the reference frame. Four pairs of entangled photons (biphotons) are sent through four interferometers: three interferometers are used to determine the user's spatial position, and an additional interferometer ... |
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