Casimir impact and the MIR test

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Rundown. The quantum vacuum and its minute consequencesThe static Casimir impact: hypothesis and experimentsFriction impacts of the vacuum and the dynamical Casimir effectThe MIR test proposition. The quantum vacuum. Quantum vacuum is not discharge but rather is characterized as the minimun of the vitality of any fieldIts impacts are a few at tiny level:Lamb shiftLand

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G. Carugno INFN Padova Casimir impact and the MIR try D. Zanello INFN Roma 1

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The quantum vacuum and its infinitesimal outcomes The static Casimir impact: hypothesis and examinations Friction impacts of the vacuum and the dynamical Casimir impact The MIR explore proposition Summary

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Quantum vacuum is not vacant but rather is characterized as the minimun of the vitality of any field Its belongings are a few at minuscule level: Lamb move Landè consider (g-2) Mean existence of a segregated molecule The quantum vacuum

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The static Casimir impact This is a plainly visible impact of the quantum vacuum, associated with vacuum geometrical control HBG Casimir 1948: the drive between two directing parallel plates of zone S separated by d

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Experimental checks The main critical analyses were carried on in a circle plane arrangement. The applicable recipe is R is the circle sweep

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Results of the Padova test (2002) First estimation of the Casimir impact between parallel metallic surfaces

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Fulling and Davies (1976): impacts of the vacuum on a moving mirror Steady movement ( Lorentz invariance ) Uniformly quickened movement ( Free falling lift ) Non uniform speeding up ( Friction !): too frail to possibly be perceptible Friction impacts of the vacuum N ph ~ W T ( v/c ) 2

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GT Moore (1970): proposes the utilization of a RF EM pit for photon creation Dodonov et al (1989), Law (1994), Jaeckel et al (1992): brought up the significance of parametric reverberation condition keeping in mind the end goal to duplicate the impact Amplification utilizing a RF depression w m = excitation recurrence w 0 = pit reverberation recurrence w m = 2 w 0

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The parametric reverberation is a known idea both in arithmetic and material science In science it originates from the Mathieu conditions In material science it is known in mechanics (variable length swing) and in hardware (wavering circuit with variable capacitor) Parametric reverberation

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Theoretical forecasts Linear development A.Lambrecht, M.- T. Jaekel, and S. Reynaud, Phys. Rev. Lett. 77 , 615 (1996) 2. Exponential development V. Dodonov, et al Phys. Lett. A 317 , 378 (2003); M. Crocce, et al Phys. Rev. A 70, (2004); M. Uhlmann et al Phys. Rev. Lett. 93, 19 (2004) t is the excitation time

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Is vitality monitored? E out E out E in E in E out t Srivastava (2005):

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Resonant RF Cavity In a practical set-up a 3-diminish depression has a swaying divider. W m Cavity with measurements ~ 1 - 100 cm have reverberation recurrence changing from 30 GHz to 300 MHz . ( microwave hole ) Great exploratory test : movement of a surface at frequencies amazingly extensive to match depression reverberation and with substantial speed ( b =v/c)

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Mechanical movement . Solid constraint for a moving layer: INERTIA Very wasteful method: to move the electrons giving the reflectivity one needs to move additionally the cores with substantial misuse of vitality Maximum dislodging got up and coming of the request of 1 nm Effective movement . Understand a period variable mirror with driven reflectivity (Yablonovitch (1989) and Lozovik (1995) Surface movement

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Time variable mirror Resonant depression with time variable mirror MIR Experiment

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The Project Dino Zanello Rome Caterina Braggio Padova Gianni Carugno Giuseppe Messineo Trieste Federico Della Valle Giacomo Bressi Pavia Antonio Agnesi Federico Pirzio Alessandra Tomaselli Giancarlo Reali Giuseppe Galeazzi Legnaro Labs Giuseppe Ruoso MIR – RD 2004-2005 R & D financed by National Institute for Nuclear Physics (INFN) MIR 2006 APPROVED AS Experiment.

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Time variable mirror Our approach Taking motivation from proposition by Lozovik (1995) and Yablonovitch (1989) we create the limit change by light brightening of a semiconductor piece put on a hole divider Semiconductors under enlightenment can change their dielectric properties and get to be from totally straightforward to totally intelligent for chose wavelentgh. A prepare of laser heartbeats will create a recurrence controlled variable mirror and consequently if the change of the limit conditions satisfy the parametric reverberation condition this will bring about the Dynamical Casimir impact with the joined nearness of high recurrence , huge Q and extensive speed

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Expected outcomes Complete portrayal of the test mechanical assembly has been finished by V. Dodonov et al (see talk in QFEXT07). V Dodonov and A V Dodonov "QED impacts in a hole with time-subordinate thin semiconductor chunk energized by laser beats" J Phys B 39 (2006) 1-18 Calculation in light of sensible trial conditions, t semiconductor recombination time ,   10-30 ps  semiconductor portability ,   1 m 2/(V s) () semiconductor light retention coefficient t semiconductor thickness , t  1 mm laser: 1 ps beat term, 200 ps periodicity, 10-4 J/beat (a, b, L) pit measurements Expected photons N > 10 3 for each prepare of shots

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Photon era in addition to damping A 0 = 10 D = 2 mm  = b = 3 10 4 cm 2/Vs  = 2.5 GHz  = 12 cm (b = 7 cm, L = 11.6)

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Measurement set-up Cryostat divider The entire set-up is partitioned into Laser framework Resonant depression with semiconductor Receiver chain Data procurement and general planning

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Experimental issues Effective mirror the semiconductor when lit up acts as a metal (in the microwave band) timing of the era and recombination forms quality element of the cavity with embedded semiconductor conceivable commotion originating from era/recombination of bearers Laser framework probability of high recurrence exchanging beat vitality for finish reflectivity number of successive heartbeats Detection framework least discernible flag clamor from blackbody radiation

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Semiconductor as a reflector Reflection bends for Si and Cu Light heartbeat Experimental set-up Results: Perfect reflectivity for microwave Si, GaAs: R=1; Light vitality to make a decent mirror ≈ 1 m J/cm 2 Time ( m s)

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Semiconductor I The look for the correct semiconductor was long and upsetting, yet we figured out how to locate the correct material Requests: t ~ 10 ps , m ~ 1 m 2/(V s) Neutron Irradiated GaAs Irradiation is finished with quick neutrons (MeV) with a dosage ~ 10 15 neutrons/cm 2 (performed by a gathering at ENEA - ROMA). These procedure while keeping a high versatility diminishes the recombination time in the semiconductor High affectability estimations of the recombination time performed on our specimens with the THz pump and test system by the gathering of Prof. Krotkus in Vilnius (Lithuania)

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Semiconductor II: recombination time Results acquired from the Vilnius bunch on Neutron Irradiated GaAs Different dosages and at various temperatures The strategy permits to quantify the reflectivity from which one ascertain the recombination time 1. Same temperature T = 85 K 2. Same dosage (7.5E14 N/cm 2 ) Estimated t = 18 ps

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Semiconductor III: portability Mobility can be generally evaluated for correlation with a known specimen from the past estimations and from estimations of non illuminated examples. m ~ 1 m 2/(V s) We are setting up a contraption for measuring the item mt utilizing the Hall impact. From writing one finds that little change is normal amongst lighted and non illuminated specimens at our dosage

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Cavity with semiconductor divider Fundamental mode TE 101 : the electric field E Computer model of a depression with a semiconductor wafer on a divider a = 7.2 cm b = 2.2 cm l = 11.2 cm Q L =  measured ≈ 3 · 10 6 600 m thick section of GaAs

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Cryostats old new Superconducting pit Cavity geometry and size upgraded after Dodonov's counts Niobium: 8 x 9 x 1 cm 3 Semiconductor holding top Antenna opening Q esteem ~ 10 7 for the TE 101 mode resounding @ 2.5 GHz No adjustments in Q because of the nearness of the semiconductor The new one has a 50 l LHe vessel Working temperature 1 - 8 K

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(Cryogenic) Electronics I Final objective is to quantify around 10 3 photons @ 2.5 GHz Use a low commotion cryogenic speaker and after that a superheterodyne location chain at room temperature Picture of the room temperature chain The cryogenic enhancer CA has 37 dB pick up permitting to disregard clamor originating from whatever remains of the finder anchor Special care must be taken in the cooling of the intensifier CA and of the link associating the pit recieving wire to it CA PA

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Electronics II: estimations Motorized control of the get reception apparatus Superconducting pit ~ 10 cm Cryogenic speaker

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Electronics III: clamor estimation Using a warmed 50 W resistor it is conceivable to get clamor temperature of the principal enhancer and the aggregate pick up of the beneficiary chain 2. Finish chain 1. Enhancer + PostAmplifier

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Sensitivity The power P measured by the FFT is: k B - Boltmann's steady G - add up to pick up B - data transfer capacity T N - intensifier clamor temperature T R - 50 W genuine temperature Results: T N1 = T N2 No additional commotion included the room temperature chain G 1 = 72 dB = 1.6 10 7 G tot = 128 dB = 6.3 10 12 The clamor temperature T N = 7.2 K compares to 1 10 - 22 J For a photon vitality = 1.7 10 - 24 J sensitivity ~ 100 photons

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Black Body Photons in Cavity at Resonance Noise 50 Ohm Resistor at R.T. Clamor Signal from TE101 Cavity at R.T. Hole Noise versus Temperature

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Laser framework I Pulsed laser with rep rate ~ 5 GHz, beat vitality ~100 m J, prepare of 10 3 - 10 4 beats, somewhat recurrence tunable ~ 800 nm Laser ace oscillator 5 GHz, low power Pulse picker Optical enhancer Total number of heartbeats restricted by the vitality accessible in the optical speaker Each prepare rehashed each couple of sec