ZEROPOINT FLUCTUATIONS AND DARK ENERGY IN JOSEPHSON JUNCTIONS

2007 ◽  
Vol 07 (02) ◽  
pp. C27-C35 ◽  
Author(s):  
CHRISTIAN BECK ◽  
MICHAEL C. MACKEY
Keyword(s):  
Dark Energy ◽  
Josephson Junctions ◽  
Quantum Noise ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Noise Spectrum ◽  
Standard View ◽  
Fluctuation Dissipation ◽  
Fluctuation Dissipation Theorem ◽  
The Subject

We discuss the possibility that vacuum fluctuations underlying dark energy could lead to measurable effects for the quantum noise spectrum in Josephson junctions [C. Beck, M. C. Mackey, Phys. Lett. B605, 295 (2005)]. We argue that a recent discussion of Jetzer and Straumann [Phys. Lett. B606, 77 (2005)] relating the measured noise spectrum in Josephson junctions to van der Waals forces is incorrect. The measured noise spectrum in Josephson junctions is a consequence of the fluctuation dissipation theorem and the Josephson effect and has nothing to do with van der Waals forces. Consequently, the argument of Jetzer and Straumann does not shed any light on whether dark energy can or cannot be measured using superconducting Josephson devices. We also point out that a more recent paper of Jetzer and Straumann [Phys. Lett. B639, 57 (2006)] claiming that 'zeropoint energies do not not show up in any application of the fluctuation dissipation theorem' violates the standard view on the subject.

Self-Assembly of a Chiral Cubic Three-Connected Net from the High Symmetry Molecules C60 and SnI4

2020 ◽  
Author(s):  
Daniel B. Straus ◽  
Robert J. Cava
Keyword(s):  
Organic Synthesis ◽  
Self Assembly ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
High Symmetry ◽  
Molecular Chirality ◽  
Chiral Materials ◽  
Self Assembled ◽  
Chiral Centers

The design of new chiral materials usually requires stereoselective organic synthesis to create molecules with chiral centers. Less commonly, achiral molecules can self-assemble into chiral materials, despite the absence of intrinsic molecular chirality. Here, we demonstrate the assembly of high-symmetry molecules into a chiral van der Waals structure by synthesizing crystals of C<sub>60</sub>(SnI<sub>4</sub>)<sub>2</sub> from icosahedral buckminsterfullerene (C<sub>60</sub>) and tetrahedral SnI4 molecules through spontaneous self-assembly. The SnI<sub>4</sub> tetrahedra template the Sn atoms into a chiral cubic three-connected net of the SrSi<sub>2</sub> type that is held together by van der Waals forces. Our results represent the remarkable emergence of a self-assembled chiral material from two of the most highly symmetric molecules, demonstrating that almost any molecular, nanocrystalline, or engineered precursor can be considered when designing chiral assemblies.

scholarly journals Nanotube‐Based 1D Heterostructures Coupled by van der Waals Forces

Small ◽  
2021 ◽  
pp. 2102585
Author(s):  
Sofie Cambré ◽  
Ming Liu ◽  
Dmitry Levshov ◽  
Keigo Otsuka ◽  
Shigeo Maruyama ◽  
...  
Keyword(s):  
Van Der Waals ◽  
Van Der Waals Forces

scholarly journals Tuning adlayer-substrate interactions of graphene/h-BN heterostructures on Cu(111)–Ni and Ni(111)–Cu surface alloys

RSC Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1916-1927
Author(s):  
Jianmei Huang ◽  
Qiang Wang ◽  
Pengfei Liu ◽  
Guang-hui Chen ◽  
Yanhui Yang
Keyword(s):  
Long Range ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Alloy Surface ◽  
Surface Alloys ◽  
Substrate Interactions

The evolution of the interface and interaction of h-BN and graphene/h-BN (Gr/h-BN) on Cu(111)–Ni and Ni(111)–Cu surface alloys versus the Ni/Cu atomic percentage on the alloy surface were comparatively studied by DFT-D2, including critical long-range van der Waals forces.

scholarly journals The Response to Stratospheric Forcing and Its Dependence on the State of the Troposphere

2009 ◽  
Vol 66 (7) ◽  
pp. 2107-2115 ◽  
Author(s):  
Cegeon J. Chan ◽  
R. Alan Plumb
Keyword(s):  
Time Scale ◽  
Equilibrium Temperature ◽  
Intrinsic Variability ◽  
Winter Solstice ◽  
Fluctuation Dissipation ◽  
Fluctuation Dissipation Theorem ◽  
Order Of Magnitude ◽  
Leading Mode ◽  
Set Up ◽  
Hemisphere Winter

Abstract In simple GCMs, the time scale associated with the persistence of one particular phase of the model’s leading mode of variability can often be unrealistically large. In a particularly extreme example, the time scale in the Polvani–Kushner model is about an order of magnitude larger than the observed atmosphere. From the fluctuation–dissipation theorem, one implication of these simple models is that responses are exaggerated, since such setups are overly sensitive to any external forcing. Although the model’s equilibrium temperature is set up to represent perpetual Southern Hemisphere winter solstice, it is found that the tropospheric eddy-driven jet has a preference for two distinct regions: the subtropics and midlatitudes. Because of this bimodality, the jet persists in one region for thousands of days before “switching” to another. As a result, the time scale associated with the intrinsic variability is unrealistic. In this paper, the authors systematically vary the model’s tropospheric equilibrium temperature profile, one configuration being identical to that of Polvani and Kushner. Modest changes to the tropospheric state to either side of the parameter space removed the bimodality in the zonal-mean zonal jet’s spatial distribution and significantly reduced the time scale associated with the model’s internal mode. Consequently, the tropospheric response to the same stratospheric forcing is significantly weaker than in the Polvani and Kushner case.

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