Repulsive Casimir Effects

Milton, Kimball A.; Abalo, E. K.; Parashar, Prachi; Pourtolami, Nima; Brevik, Iver; Ellingsen, Simen Å.

doi:10.1142/s0217751x12600147

Cited by 11 publications

(12 citation statements)

References 25 publications

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“…However, practical atom chip schemes for interferometry with a wide dynamic range and versatile geometries are still very much sought after [23][24][25][26][27][28] . Such schemes may enable, for example, sensitive probing of classical or quantum properties of solid-state nanoscale devices and surface physics (for example, refs [29][30][31][32][33]. This is expected to enhance considerably the power of non-interferometric measurements with ultracold atoms on a chip, which have already contributed, for example, to the study of long-range order of current fluctuations in thin films 34 , the Casimir-Polder force [35][36][37][38] and Johnson noise from a surface 39 .…”

mentioning

confidence: 99%

Coherent Stern–Gerlach momentum splitting on an atom chip

2013

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In the Stern-Gerlach effect, a magnetic field gradient splits particles into spatially separated paths according to their spin projection. The idea of exploiting this effect for creating coherent momentum superpositions for matter-wave interferometry appeared shortly after its discovery, almost a century ago, but was judged to be far beyond practical reach. Here we demonstrate a viable version of this idea. Our scheme uses pulsed magnetic field gradients, generated by currents in an atom chip wire, and radio-frequency Rabi transitions between Zeeman sublevels. We transform an atomic Bose-Einstein condensate into a superposition of spatially separated propagating wavepackets and observe spatial interference fringes with a measurable phase repeatability. The method is versatile in its range of momentum transfer and the different available splitting geometries. These features make our method a good candidate for supporting a variety of future applications and fundamental studies.

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confidence: 99%

Coherent Stern–Gerlach momentum splitting on an atom chip

2013

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“…It can be easily seen (and as is also explained in detail, e.g., in [18]), that this spatial profile affects the Hamiltonian by introducing a weighted interaction between the atom and the field modes, with the weight equal to the Fourier transform of the spatial profile (13). Here, this is…”

Section: B Contribution Of the Diamagnetic Termmentioning

confidence: 87%

“…Modifying the interaction to take into account the atomic spatial profile (13), hence changes the Hamiltonian (7) to:…”

Section: B Contribution Of the Diamagnetic Termmentioning

confidence: 99%

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Casimir forces on atoms in optical cavities

2014

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Casimir-type forces, such as those between two neutral conducting plates, or between a sphere, atom or molecule and a plate have been widely studied and are becoming of increasing significance, for example, in nanotechnology. A key challenge is to better understand, from a fundamental microscopic approach, why the Casimir force is in some circumstances attractive and in others repulsive. Here, we study the Casimir-Polder forces experienced by small quantum systems such as atoms or molecules in an optical cavity. In order to make the problem more tractable, we work in a 1+1 dimensional setting, we take into account only the ground state and first excited state of the atom and we model the electromagnetic field as a scalar field with Dirichlet or Neumann boundary conditions. This allows us to determine the conditions for the Casimir force to be attractive or repulsive for individual atoms, namely through the interplay of paramagnetic and diamagnetic vacuum effects. We also study the microscopic-macroscopic transition, finding that as the number of atoms in the cavity is increased, the atoms start to affect the Casimir force exerted on the cavity walls similarly to a dielectric medium.

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“…where we dropped a term independent of s that does not contribute to the free energy. We add (17), (21), (23) and (25), and find ζ(s) when…”

Section: Zeta Function Evaluationmentioning

confidence: 99%

Finite temperature Casimir effect for massive scalars in a magnetic field

Erdas

Seltzer

2014

Int. J. Mod. Phys. A

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The finite temperature Casimir effect for a charged, massive scalar field confined between very large, perfectly conducting parallel plates is studied using the zeta function regularization technique. The scalar field satisfies Dirichlet boundary conditions at the plates and a magnetic field perpendicular to the plates is present. Four equivalent expressions for the zeta function are obtained, which are exact to all orders in the magnetic field strength, temperature, scalar field mass, and plate distance. The zeta function is used to calculate the Helmholtz free energy of the scalar field and the Casimir pressure on the plates, in the case of high temperature, small plate distance, strong magnetic field and large scalar mass. In all cases, simple analytic expressions of the zeta function, free energy and pressure are obtained, which are very accurate and valid for practically all values of temperature, plate distance, magnetic field and mass.

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Repulsive Casimir Effects

Cited by 11 publications

References 25 publications

Coherent Stern–Gerlach momentum splitting on an atom chip

Coherent Stern–Gerlach momentum splitting on an atom chip

Casimir forces on atoms in optical cavities

Finite temperature Casimir effect for massive scalars in a magnetic field

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