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Comments and Questions about Dark Energy, Dark Matter and T-DEE (Tabletop-Dark Energy Experiments)

Comments and Questions about Dark Energy, Dark Matter and T-DEE (Tabletop-Dark Energy Experiments). Roger Koch – IBM Watson Labs Yasar Onel, University of Iowa Elie Track – Hypres Inc David Winn – Fairfield University winn@mail.fairfield.edu

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Comments and Questions about Dark Energy, Dark Matter and T-DEE (Tabletop-Dark Energy Experiments)

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  1. Comments and Questions aboutDark Energy, Dark MatterandT-DEE(Tabletop-Dark Energy Experiments) Roger Koch – IBM Watson Labs Yasar Onel, University of Iowa Elie Track – Hypres Inc David Winn – Fairfield University winn@mail.fairfield.edu Help: Dan Prober, Yale Applied Physics;

  2. A mysterious and interesting Universe WMAP Position 1st peak WT=1.02 +/- 0.02 Flat universe Ratio (2/1) peaks WB =0.046 +/- 0.006 Ordinary Matter: 4% 1/3 Dark Matter? 2/3 Dark Energy? • CMB, + SN, clusters, galaxies redshift surveys, Weak Lensing, … • Cold Dark MatterandCosmological constant ??? Definition:W=r/rc (rc=10-29 g/cm3) Ordinary Matter: 4%

  3. Modern Cosmology:Dark Matter, Dark Energy Universe by Aristotle Are we the new Ptolemeans? Modern epicycles? Need for a conceptual Revolution?

  4. Dark Energy • Dark Energy: • - Observationally Exists (w=-1? Yes - UCLA 2006) • String theory may provide landscape for DE…. • BUT Many Proposals to “explain” , or modifications to General Relativity/QG ….. • Quintessence? • Phantom Fields? • Quintom Fields? • Born-Infeld Quantum Condensates? • Chaplygin Gas? • Fields with Non-Standard Kinetic terms?……… • All invoke New Physics… • - Dark Energy is Still a Problem to “Explain” from Q/FT

  5. A Quantum Gravity effect? • - What is the average density of the Universe that is measured by cosmologists? • If it has to do with Quantum Gravity Vacuum fluctuations, need to unify General Relativity and Gravity! Loop Quantum Gravity Ashtekar, Smolin, Rovelli, etc… SuperStrings …….. Extensions to GR Moffat MOND Milgrom, Beckenstein Negative energies Henry-Couannier QFT in curved spacetime

  6. Alternative views on Dark Energy Sakharov (1968) Alternative views gravitation is induced=/= fundamental interaction <== fluctuations of quantum vacuum Interpretation of G. Volovik (gr-qc/0304061) The Universe in a Helium droplet, Clarendon Press, Oxford (2003) Analogy superfluids 3He, 4He Systems with Fermi and Bose quantum fields describing the interactions of elementary quasiparticles, with each other and with the vacuum

  7. Field Vacuum Energy - Does it Exist? • - Essentially all QFT give Quartically Infinite Vacuum Energy • - Cut-off at Planck mass gives ~10120 times too much • Exact SuSY? Yes, except it must-be/it-is broken… • Higgs fields only Add Vacuum Energy….. • We need to find an excuse why the vacuum energy is not • observable, or why only a small fraction of it survives… • Mainly just a belief that vacuum energy is not • gravitationally active (i.e. fields do not couple), just like DE? • The Vacuum Energy Density is Still a Problem! • Is it related to Dark Energy Density?

  8. Zero Point Fluctuations - They Exist! • Zero-Point Energy - h/2 - no oscillator is at rest - px~h • -> A collection of oscillators integrated over  also yields a quartically divergent energy density, just like QFT! • Exactly what is ZPE? • [enlightening reference C.W. Gardiner, Quantum Noise, (1991) Springer, Berlin] • A ~PUZZLING ILLUSTRATION: • Vacuum fluctuations produce noise in dissipative systems. Why? • -Classically, a dissipative system with [x,p] will end up at a fixed point with p=0, since all kinetic energy is dissipated. • Quantum Mechanically, violates Uncertainty Principle: p=0. • The Noise acts as a fluctuating driving force, so that p is not fixed, and the uncertainty principle is satisfied at all times. • (If the ZPE is related to DE/Vacuum Energy, perhaps the Dark Energy is the origin of quantum mechanics!)

  9. Testing the Dark Energy Paradigm Where is progress to come from? + Phenomenology + Observations + Theory ! + What about testing Physics in the Lab?

  10. Zero point energy and vacuum fluctuations Planck’s second theory of black body radiation Average energy of collection of oscillators • Zero point energy term • Experimental effects: • Lamb shift - NO! (Jaffe, 2005) • «spontaneous » emission - NO! • Casimir effect - NO! • van der Waals forces - NO! • Interpretation of Aharonov-Bohm effect • Bragg, Compton scattering ~no Well known black-body spectrum Look eg, @ Spectra of Nyquist noise in electrical circuits

  11. Evidence for ZPE term From R.Koch et al., Phys. Rev. B, 26, 74, (1982).

  12. Dark energy cutoff? Beck and Mackey astro-ph/0406504

  13. Multi-TeraHz Josephson junctions ? From Koch et al., Phys. Rev. B, 26, 74,(1982). Possible cutoff? Interesting lab experiments ? A factor 3 to gain from 1982 experiment Lorentz Inv.? Yes! String Theory ! [Frampton, 2005]

  14. To measure n > THz:Josephson Junctions ~ perfect voltage <-> frequency converter ~6 THz at 4 mV! - The Nyquist noise in the shunt resistor R is mixed down to the much lower frequency of the LC tank circuit by the JJ. - At any J selected by the bias voltage V, the amplitude of the lower frequency is ~amplitude of the noise in R at J. Where

  15. Optimizing the Josephson Junction o = h/2e Io = critical current L,C - geometry of JJ Vmax < Vgap -> max < 2eVgap/h ~1.5 THz/mV Assume the Nyquist Noise in a shunt resistor R is modeled by harmonic oscillators In limit eV>>kT, noise becomes solely ZPF in R Note: When I<<Io, transitions so slow that single Particle must be replaced by wave-packet - MQT

  16. It’s a Calibration Experiment! • This is NOT a relative experiment - ZPE everywhere! • B = 0 -> Superconducting Bag • System Gain: Calibrated by Nyquist Noise in Rcal • Mixing Coefficient - (Io/I)2/2 • Tank Circuit Losses • 1/f noise • T from I2R in shunt resistor • (de)Coupling of 300oK noise

  17. Improvements to Reach f>2 THz • Increase  > 1.7 THz - limit by Vgap • Decrease T to milliK or less (from 1.6K) • 1/f - increase IF to 100 MHz (from 100 kHz) • Signal - Use SQUID amplifier in dewar (not xformer) • Shunt Resistor - “dirty Au” MBE (instead of CuAl) • PreAmp - Use cooled parametric amplifiers • More: Materials Systems, Geometries of Shunt, JJ • Nb limited to Vgap ~1 mV -  < 1.5 THz • MgB2 - 2.2 mV  < 3.3 THz • Nb-AlN-NbN - 3.55 mV  < 5 THz • Others: (K,Ba)Bi, C60, CaCuO,Bi2212

  18. Large Vgapmax~5THz VP Koshlets et al. IREE Moscow -2005

  19. Integrated SC Circuitry High Sensitivity ADC(~1 ) Superconducting IC using 6000 Josephson junctions. Similar technology would be used for a JJ amplifier. From Hypres, Inc

  20. Irreducible Noise in DC SQUIDS Appl.Phys.Letters 50(12) 23 (1987) 12 SQUIDs Size varies x200 Inductance varies x20 3 materials systems

  21. Irreducible Noise in DC SQUIDS FC.Wellstood, C.Urbina, J.Clarke Appl.Phys.Lett.50,23 (1987) 1/f0.66 Remarkably, as T decreases below 1o, the spread in the excess over 1/f noise converges and flattens out, only x2 different for 12 SQUIDs, despite enormous differences in the size of the SQUIDS, their linewidths, critical currents, and loop materials. For T>1o, the noise varies by more than an order of magnitude! There is no good theory of this…

  22. Irreducible Noise in SQUIDs:Systemic Errors, or Signal of New Phenomena? This noise is now of concern in QUBITs - coherence time The energy/volume is “interesting” (0.0001-10 GeV/m3), depending on the calculation of the volume and times involved…. Could this be a signal of Dark Energy <=> Vacuum Fluctuations? …..Or Dark Matter?

  23. Possible Investigation A) Re-Do this experiment • Vary sizes, geometry, materials more systematically (Taguchi Matrix), and over even larger ranges. • Lower T to <1 mK to see extrapolation • Extend to lower, higher frequencies • Ultra-high purity materials system (no magnetic) • Purposeful impurities, including magnetic moments • Many more materials systems • SQUID circuitry, better shielding, cooled externals B) Find a condensed matter theory, or C) Imagine how DE/DM/<> might explain!

  24. Go with the Flow!

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