17,330 research outputs found
On the Machian Origin of Inertia
We examine Sciama's inertia theory: we generalise it, by combining rotation
and expansion in one unique model, we find the angular speed of the Universe,
and we stress that the theory is zero-total-energy valued. We compare with
other theories of the same null energy background. We determine the numerical
value of a constant which appears in the Machian inertial force expression
devised by Graneau and Graneau[2], by introducing the above angular speed. We
point out that this last theory is not restricted to Newtonian physics as those
authors stated but is, in fact, compatible with other cosmological and
gravitational theories. An argument by Berry[7] is shown in order to "derive"
Brans-Dicke relation in the present context.Comment: 10 pages including front one. New version was accepted to publication
by Astrophysics and Space Scienc
Influence of qubit displacements on quantum logic operations in a silicon-based quantum computer with constant interaction
The errors caused by qubit displacements from their prescribed locations in
an ensemble of spin chains are estimated analytically and calculated
numerically for a quantum computer based on phosphorus donors in silicon. We
show that it is possible to polarize (initialize) the nuclear spins even with
displaced qubits by using Controlled NOT gates between the electron and nuclear
spins of the same phosphorus atom. However, a Controlled NOT gate between the
displaced electron spins is implemented with large error because of the
exponential dependence of exchange interaction constant on the distance between
the qubits. If quantum computation is implemented on an ensemble of many spin
chains, the errors can be small if the number of chains with displaced qubits
is small
Non-Resonant Effects in Implementation of Quantum Shor Algorithm
We simulate Shor's algorithm on an Ising spin quantum computer. The influence
of non-resonant effects is analyzed in detail. It is shown that our ``''-method successfully suppresses non-resonant effects even for relatively
large values of the Rabi frequency.Comment: 11 pages, 13 figure
Silicon solar cells improved by lithium doping
Results of conference on characteristics of lithium-doped silicon solar cells and techniques required for fabrication indicate that output of cells has been improved to point where cells exhibit radiation resistance superior to those currently in use, and greater control and reproducibility of cell processing have been achieved
The Agent Orange Veteran Payment Program
This thesis discusses how to enhance the public discussion of moral and political questions. Enhancing public âdeliberationâ is desirable since it provides citizens with influence, it enables coming to an understanding, and it ensures legitimacy. The concept of ethico-political judgment, with its two conditions, is elaborated on as an ideal that suggests how we should deliberate. In order to understand how we actually deliberate, an empirical inquiry into the public discourse on prenatal diagnosis and screening in the Netherlands and Sweden is conducted. On the basis of Kantâs ethics and his theory of the faculty of judgment, the two conditions for public deliberation are developed. These conditions are the giving of and asking for normative reasons as well as aiming at impartiality of judgment. Normative reasons are prescriptive, universal, and internal and these are related to Kantâs ethics. Impartiality is related to Kantâs âenlarged thoughtâ, to think from the standpoint of others, as well as Kantâs practical philosophy. We need to think from the standpoints of others in order to consider whether or not the principle of our action applies to all. Four thematic foci in the public discourse on prenatal diagnosis are investigated â the unborn life, attitudes toward the disabled, implications of new choices, and the limits of medicine. The conclusion is that â if we wish to enhance public deliberation on the basis of the two conditions of ethico-political judgment â we should deal with both interpretive differences over universal principles (such as respect for autonomy and human dignity) and varying representations of âthe otherâ (such as the fetus, disabled persons, mothers-to-be, and future parents).I denna avhandling diskuteras hur offentlig diskussion kring moraliska och politiska frĂ„gor kan intensifieras. Att intensifiera offentlig diskussion Ă€r önskvĂ€rt för att ge medborgare inflytande, för att frĂ€mja förstĂ„else och för att skapa legitimitet. Begreppet etisk-politisk bedömning utvecklas som ett ideal för hur vi bör diskutera. För att undersöka hur vi faktiskt diskuterar görs en empirisk undersökning av det offentliga samtalet om fosterdiagnostik i NederlĂ€nderna och Sverige. Med utgĂ„ngspunkt i Kants etik och hans teori om omdömesförmĂ„gan utvecklas tvĂ„ villkor för offentlig diskussion. Dessa villkor Ă€r att ge och efterfrĂ„ga normativa skĂ€l och att strĂ€va efter opartiskhet av omdömesförmĂ„gan. Normativa skĂ€l Ă€r preskriptiva, universella och interna. Begreppet utvecklas utifrĂ„n Kants etik. Opartiskhet baseras pĂ„ Kants âutvidgade tĂ€nkandeâ: att tĂ€nka utifrĂ„n andras perspektiv. Denna idĂ© relateras till Kants praktiska filosofi. Det âutvidgade tĂ€nkandetâ innebĂ€r att vi tar stĂ€llning till om principen som vi vĂ€ljer för en handling gĂ€ller alla. Fyra teman i det offentliga samtalet om fosterdiagnostik analyseras â det ofödda livet, attityder gentemot handikappade, implikationer av nya val och den medicinska praktikens grĂ€nser. Slutsatsen Ă€r att om vi önskar intensifiera offentlig diskussion med utgĂ„ngspunkt i de tvĂ„ villkor som utvecklas, bör vi ta itu med tolkningsskillnader nĂ€r det gĂ€ller universella principer (som respekt för autonomi och mĂ€nniskovĂ€rde) samt olika representationer av âden andraâ (som fostret, handikappade, gravida kvinnor och blivande förĂ€ldrar)
Creation of entanglement in a scalable spin quantum computer with long-range dipole-dipole interaction between qubits
Creation of entanglement is considered theoretically and numerically in an
ensemble of spin chains with dipole-dipole interaction between the spins. The
unwanted effect of the long-range dipole interaction is compensated by the
optimal choice of the parameters of radio-frequency pulses implementing the
protocol. The errors caused by (i) the influence of the environment,(ii)
non-selective excitations, (iii) influence of different spin chains on each
other, (iv) displacements of qubits from their perfect locations, and (v)
fluctuations of the external magnetic field are estimated analytically and
calculated numerically. For the perfectly entangled state the z component, M,
of the magnetization of the whole system is equal to zero. The errors lead to a
finite value of M. If the number of qubits in the system is large, M can be
detected experimentally. Using the fact that M depends differently on the
parameters of the system for each kind of error, varying these parameters would
allow one to experimentally determine the most significant source of errors and
to optimize correspondingly the quantum computer design in order to decrease
the errors and M. Using our approach one can benchmark the quantum computer,
decrease the errors, and prepare the quantum computer for implementation of
more complex quantum algorithms.Comment: 31 page
Effects of solar proton flares on the power output of solar cells having various configurations
Solar proton flare effects on silicon photovoltaic power system for deep space mission
Stability of the Ground State of a Harmonic Oscillator in a Monochromatic Wave
Classical and quantum dynamics of a harmonic oscillator in a monochromatic
wave is studied in the exact resonance and near resonance cases. This model
describes, in particular, a dynamics of a cold ion trapped in a linear ion trap
and interacting with two lasers fields with close frequencies. Analytically and
numerically a stability of the ``classical ground state'' (CGS) -- the vicinity
of the point () -- is analyzed. In the quantum case, the method for
studying a stability of the quantum ground state (QGS) is suggested, based on
the quasienergy representation. The dynamics depends on four parameters: the
detuning from the resonance, , where and
are, respectively, the wave and the oscillator's frequencies; the
positive integer (resonance) number, ; the dimensionless Planck constant,
, and the dimensionless wave amplitude, . For , the CGS
and the QGS are unstable for resonance numbers . For small
, the QGS becomes more stable with increasing and decreasing
. When increases, the influence of chaos on the stability of the
QGS is analyzed for different parameters of the model, , and
.Comment: RevTeX, 38 pages, 24 figure
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