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Figure 3: Schematic view <strong>of</strong> the ALPS LSW experiment. PD denotes various photo detectors, CM the coupling mirror and EM the end mirror <strong>of</strong> the resonant cavity. See the text and [23] for a description. tion, cf. Fig. 3. ALPS is the first experiment which successfully exploits a large-scale optical resonator for WISP searches. The main parts and their basic functionality are explained in [1] and reference therein. During the measurement period in the year 2009 a continuously circulating power inside the ALPS production region <strong>of</strong> around 1.2 kW at 532 nm was achieved [23]. ALPS also exploits successfully a new method to cover the gaps in the sensitivity for higher masses, where the ALP wave runs out <strong>of</strong> phase w.r.t. the phase <strong>of</strong> the laser beam, cf. Fig. 4. Introducing Ar gas at a pressure <strong>of</strong> 0.18 mbar changes the photon momentum and tunes therefore the refraction index. In the ALPS setup the γ−ALP relative phase velocity increases thereby to have an extra half oscillation length. Even if the sensitivity is lowered compared to vacuum conditions this helps to cover the higher mass gaps. ALPS RESULT ALPS took around 50 data sets (1 h frames) under different experimental conditions: with magnet on or <strong>of</strong>f, laser polarization parallel or perpendicular to the magnetic field and different gas pressures. Details on the methodology and analysis are described in [1, 23]. From the non observation <strong>of</strong> any WISP signal a 95 % confidence level on the conversion probabilty was obtained, ranging between Pγ→ϕ→γ = 1 − 10 × 10 −25 for the different experimental setups. Fig. 4 shows the ALPS results for pseudoscalar and scalar axion-like particles together with the results obtained from BMV [25], BFRT [26], GammeV [27], LIPSS [28] and OSQAR [29]. The gaps at higher masses are covered by the ALPS gas runs as described above. ALPS provide now the most stringent laboratory bounds on ALPs in the sub-eV mass range. Also for hidden photon and minicharged particle searches ALPS has achieved the highest sensitivity in the laboratory, cf. Fig. 5. The ALPS LSW results on hidden photon search fills the gap between lab searches for deviations from Coulomb’s law and astrophysical bounds. Remarkable, with the achieved sensitivity ALPS almost completely rules out the hint <strong>of</strong> WMAP and large-scalestructure probes with non-standard radiation density contribution due to hidden photons, cf. [23] and references therein. OUTLOOK The present generation <strong>of</strong> laboratory experiments searching for WISPs has not found any evidence for those elusive particles. It’s worth mentioning that this probes for new physics (if ALPs exist) at the 100 TeV scale 1 already. The physics case for WISPs is still strengthening due to ongoing theoretical studies and puzzling observations in astrophysics as mentioned above. The QCD axion itself remains a “holy grail” for particle physics. To solve the CP problem in QCD and understand Dark Matter with one stroke is very alluring. Perhaps even Dark Energy will find its explanation in the WISP sector via the detection <strong>of</strong> “chameleons” [31]. Due to these prospects attempts are ongoing to largely improve all components <strong>of</strong> LSW experiments. Usually LSW experiments shine laser light through long and tight magnet bores. With the help <strong>of</strong> resonant optical cavities effective laser light powers around 100 kW might be possible in future. The ALPS collaboration is presently preparing such a setup. ALPS has used one spare HERA dipole magnet to achieve the results mentioned above. At DESY we study now the possibility <strong>of</strong> an experiment with up to 20+20 HERA dipoles. Most <strong>of</strong> the present-day LSW experiments use commercial CCD cameras to search for reconverted photons from WISPs behind the wall. In the future the detection sensitivity might be enhanced considerably by using transition edge sensors (TES) [32, 33]. Here a sensor is cooled down to about 100 mK and operated in the transition region be- 1 The axion-to-photon coupling g is given by g = α · gγ/πfα, where fα denotes the new energy scale and gγ a factor derived from theory expected to vary by about an order <strong>of</strong> magnitude for the QCD axion.
Figure 4: Exclusion limit (95% C.L.) for pseudoscalar (top) and scalar (bottom) axion-like particles obtained by the ALPS experiment from vacumm and gas runs together with the results from various other LSW experiments [23], see the text for details. Dashed and dotted lines show the bounds derived from the PVLAS measurement on ALP induced dichroism and birefringence [30]. tween a superconducting and normal conducting state. Due to the very low heat capacity <strong>of</strong> such a state the energy deposit <strong>of</strong> a single photon results in a significant temperature rise and is well measurable. TES detectors allow for essentially background-free counting <strong>of</strong> individual photons, register their arrival times and allow to estimate their energies. A new technology will be exploited to boost the sensitivity <strong>of</strong> LSW experiments even further: the challenge is to realize a second resonant optical cavity in the part <strong>of</strong> an experiment behind the wall. The idea <strong>of</strong> such a resonantly enhanced axion photon regeneration was put forward first in 1993 by F. Hoogeveen and T. Ziegenhagen [34] and independently rediscovered in 2007 by P. Sikivie, D.B. Tanner and K. van Bibber [35]. The basic idea is to set up an optical resonator also in the regeneration part <strong>of</strong> a LSW experiment very similar to the optical resonator in the first part. The second resonator effectively increases the conversion probability <strong>of</strong> a WISP into a photon. To understand this one Figure 5: ALPS exclusion limit (95% C.L.) for hidden photons (top) and minicharged particles (bottom) together with the results from various other experiments [23]. has to consider that the freely propagating WISP-related wave behind the wall <strong>of</strong> the LSW experiment comprises a very tiny electromagnetic photon component. Due to this small component the WISP might convert into a real photon. An optical resonator enhances this small component in the same way as the wave amplitude for real photons is increased. Hence the transition probability <strong>of</strong> WISPs to photons rises with the power amplification factor <strong>of</strong> an optical resonator in the second part <strong>of</strong> the LSW experiment behind the wall. Consequently the sensitivity <strong>of</strong> such a setup for the coupling constant g improves with the square root <strong>of</strong> this factor. The technical challenge is to lock the second cavity to exactly the same frequency and the same mode as the first cavity (used to enhance the effective laser photon flux) while keeping it dark in the light <strong>of</strong> photons searched for as WISP footprints. At ALPS we study different approaches to realize a regeneration cavity. Combining all the improvements mentioned above would result in a greatly improved sensitivity allowing LSW experiments to surpass present day indirect limits from astrophysics (g = 10 −10 GeV −1 ) and touch the parameter region for ALPS indicated by astrophysics phenomena
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Proceedings <stron
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Conference poster
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Preface The international conferenc
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Recent progress of
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Figure 1: The Pulse Intensity-Durat
Page 15: Figure 3: The attosecond metrology
Page 18 and 19: THE QED EFFECTIVE ACTION In quantum
Page 20 and 21: Figure 2: Turning points in the com
Page 22 and 23: [5] A. Ringwald, “Pair production
Page 24 and 25: QED IN ULTRA-INTENSE LASER FIELDS
Page 26 and 27: form e + nγL → e ′ + γ where
Page 28 and 29: ection(s) associated with the exter
Page 30 and 31: This is listed in Tab.1. The effect
Page 32 and 33: the spectrum of ph
Page 34 and 35: pf f f pi p x2 x1 k ki p pi Figure
Page 36 and 37: STRONG FIELD DYNAMICS IN HEAVY-ION
Page 38 and 39: Possible effects of</strong
Page 40 and 41: Figure 3: Flux tube structure <stro
Page 42 and 43: Abstract Yoctosecond photon pulse g
Page 44 and 45: emsstrahlung or inelastic pair anni
Page 46 and 47: Abstract Fields, Instantons, and Cu
Page 48 and 49: the dispersion relation p0 = Ep −
Page 50 and 51: CRITICAL BEHAVIOR OF CHARMONIUM: QC
Page 52 and 53: different masses m 0 i ̸= mi only
Page 54 and 55: ON THE UNRUH EFFECT ∗ Ralf Schüt
Page 56 and 57: Abstract Can we detect ”Unruh rad
Page 58 and 59: Equipartition Theorem The stochasti
Page 60 and 61: Abstract Quantum fields and static
Page 62: The relation between acceleration a
Page 65: = γ WISP ; ; ALP HP(mγ ′ > 0) .
Page 69 and 70: Probing extremely light fields via
Page 71 and 72: Figure 1: Second harmonic generatio
Page 73 and 74: Abstract Dynamical view of<
Page 75 and 76: (a) longitudinal momentum distribut
Page 77 and 78: Exact solutions of
Page 79 and 80: Pair production in heat bath Finall
Page 81: Table 1: Related ideas in strong fi
Page 84 and 85: Abstract Non-linear charge transpor
Page 86 and 87: under the assumption of</st
Page 88 and 89: Brilliant hardγ-production ande +
Page 90 and 91: each other. Thus the E field rotate
Page 92 and 93: ACKNOWLEDGMENTS This work is based
Page 94 and 95: ϵ is the energy of</strong
Page 96 and 97: of the sampling eq
Page 98 and 99: Abstract SCHWINGER LIMIT ATTAINABIL
Page 100 and 101: To find it we use the integral calc
Page 102 and 103: cloud with a size of</stron
Page 104 and 105: A way to quantify the irreversible
Page 106 and 107: Figure 4: Pair production vs time f
Page 108 and 109: of the quantum flu
Page 110 and 111: Phenomena H. Schwarz and H. Hora Ed
Page 112 and 113: In USA, LLNL has a user’s facilit
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QGP is studied by using the particl
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Fig. (1): Presentation of</
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REFERENCES [1] P.A. Franken, A.E. H
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of electron. When
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splitting, no one has succeeded to
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Abstract WIDE-BAND X-RAY OBSERVATIO
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Radiation from Rotation-Powered Pul
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2 -2 -1 keV (ph cm s keV -1 ) 0.1 0
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Zero temperature case There are sti
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M|, is realized in their case, and
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egime. As analogous to a convention
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With extremely high-peak power lase
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Abstract Flying Mirror as a tool to
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Reflected light intensity (μJ/sr/n
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4-mirror laser stacking cavity for
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CURRENT STATUS OF LFEX LASER AND EX
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which were comparable to those befo
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Abstract X-ray Emission from Magnet
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sometimes exceed the Eddington lumi
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1 0.8 0.6 0.4 0.2 B 2 z E 2 T 0.5 1
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First order quantum correction to t
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dE (1) dt = ¯he4 m 2 12πɛ0p 5 i
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Next, let us consider the origin <s
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Abstract NONCANONICAL LIE PERTURBAT
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with C (2) µ = Γ (2) µ − ˆ L
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log N (PIC particle) When the condi
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Abstract X-RAY GENERATION VIA LASER
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The electron beam is bent to the du
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INVESTIGATING THE ONE-PHOTON ANNIHI
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As a representative characteristics
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the interference terms ⟨ϕIϕh⟩
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P r o g r a m of P
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11:55 lunch & group photo [85] [Rec
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List of Participan
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