Measurement at the quantum frontier

Transcription

1 Measurement at the quantum frontier J. Ye Boulder Summer School, July 24, 2018 Quantum sensing Table-top search for new physics Many-body dynamics Marti et al., PRL (2018). S. Blatt et al., PRL (2008). Bromley et al., Nat Phys (2018).

2 Lecture outlines Lecture I Simple atomic physics Basic quantum physics Basic laser science The ingredients for control & measurement of quantum coherence Lecture II Atomic interactions Spin Hamiltonians Emergence of complexity from simple ingredients A new frontier: quantum metrology & many-body physics

3 Atomic/Molecular Ultracold Matter Precise control of quantum systems Clocks, quantum information, sensors Bloom et al., Nature 506, 71 (2014). Understanding complexities & strong correlations Superconductivity & Superfluidity Quantum magnetism Quantum chemistry Universality & scaling Contact vs. long-range Drive vs. interaction Atoms Electrons Optical lattice Ionic Crystal E

4 Precision metrology meets many-body physics Martin et al., Science 341, 632 (2013). A new generation of stable lasers 1D Lattice Signal Amplitude Silicon cavity (PTB/JILA) 0.01 Hz per laser 11 mhz linewidth: 0.4 Hz Beat frequency (Hz) Relative detuning (Hz)

5 3 degrees of freedom: electronic, nuclear, spatial n m n m + m n n m - m n nuclear electronic motional + OR + OR = n m + m n OR n m m n

6 Interactions between Fermions n x,y n z 0 1 v ee + v eg + n 1 n 2 n 2 n 1 p - wave interaction v gg

7 1D lattice clock: spin model Collective-spin S Γ ee mapping interacting fermions to bosons CC = vv eeee vv gggg 2 χχ = vv eeee + vv gggg 2vv eeee 2 Two-component BEC: Sorensen, Moller, Cirac, Zoller, Lewenstein,

8 Clock probes many-body spin dynamics Martin et al., Science 341, 632 (2013). U Quantum fluctuations correlated! U U Τ >> 1 φ

9 Collisional frequency shift θ Excitation fraction ν = H / S z Collisional shift has a linear dependence on S z = cos(θ). C θ

10 Density shifts & SU(N) symmetry Zhang et al., Science 345, 1467 (2014). Fallani (2014); Fölling (2014) SU(N): shift depends only on NN SS, not distributions NN II interrogated NN SS spectators

11 So far, interactions in a single pancake Identical fermions, p-wave dominates Multiple nuclear spins, s- and p-waves under SU(N) Uo λl/2 Uo >> ER : Tunneling negligible

12 A new regime for interactions Interactions with tunneling allowed when tunneling is allowed. J Uo λlattice /2

13 Quantum simulation wishlist Charge Motion Interactions Spin

14 Quantum simulation wishlist Quantum Hall Motion Optical lattice clocks: Charge Fractional quantum Hall Interactions Topological insulators Kondo physics Spin Magnetism

15 Quantum simulation wishlist Optical lattice clocks: Charge Motion Spin-orbit Synthetic gauge coupling fields Interactions Spin

16 Spin-orbit coupled fermion interactions Kolkowitz et al., Nature 542, 66 (2017); Bromley et al., Nature Phys. (2018). t a lattice λ clock e> e iφ e i2φ e i3φ g> λlattice /2

17 Synthetic magnetic field in the clock 813 nm 1D lattice n-2 n-1 n

18 Synthetic magnetic field in the clock 813 nm 1D lattice n-2 n-1 n e = 3 P n-2 n-1 n g = 1 S0

19 Synthetic magnetic field in the clock λl = 813 nm 1D lattice λc = 698 nm clock beam n-2 n-1 n e = 3 P0 Ωo Ωoe iφ Ωoe i2φ Ωoe inφ n-2 n-1 n g = 1 S0 Φ=πλl/λc

20 Synthetic magnetic field in the clock λl = 813 nm 1D lattice J λc = 698 nm clock beam n-2 n-1 Ωo Ωoe iφ Ωoe i2φ J J J J Φ=πλl/λc 6 n-2 Tunneling rate J n-1 n e = 3 P0 Ωoe inφ g = 1 S0 n

21 Synthetic magnetic field in the clock n=0 n=1 J e = 3 P0 Ωo n=0 J n=1 Ωoe iφ g = 1 S0

22 Synthetic magnetic field in the clock n=0 n=1 J e = 3 P0 Ωo n=0 J n=1 Ωoe iφ g = 1 S0

23 Synthetic magnetic field in the clock n=0 n=1 J e = 3 P0 Ωo n=0 J n=1 Ωoe iφ g = 1 S0

24 Synthetic magnetic field in the clock n=0 n=1 J e = 3 P0 Ωo n=0 J n=1 Ωoe iφ g = 1 S0

25 Synthetic magnetic field in the clock n=0 n=1 J e = 3 P0 Ωo n=0 J n=1 Ωoe iφ g = 1 S0

26 Synthetic magnetic field in the clock n=0 n=1 e = 3 P0 Ωo Φ Ωoe iφ n=0 n=1 g = 1 S0

27 Synthetic magnetic field in the clock λl = 813 nm 1D lattice J λc = 698 nm clock beam Φ=πλl/λc Φ Φ Φ Φ Φ Φ Φ Φ e = 3 P0 g = 1 S0

28 Spin-orbit coupling Tunneling bandwidth 4J E n = 0 e = 3 P0 ħωa 4J n = 0 g = 1 S q/ħkl

29 Spin-orbit coupling Kolkowitz et al., Nature 542, 66 (2017). 4J E n = 0 e = 3 P0 ħωa Δq = λl / λc 4J n = 0 g = 1 S q/ħkl

30 Spin-orbit coupling Kolkowitz et al., Nature 542, 66 (2017). HH qq = ΩSS xx EE qq + δδ SS zz = BB eeeeee (qq, δδ) SS EE qq = JJ [cccccc ππππ kk LL + ΦΦ cccccc ππππ kk LL ] 4J E n = 0 e = 3 P0 θ q ħωa 4J n = 0 g = 1 S q/ħkl Spin-motion locking: BB(qq ii ) ss ii

31 Spin-orbit coupled band structure - π q/kl π Density of states diverge at de/dk = 0 : van Hove singularities

32 Interacting fermions under SOC Time Time BB(qq ii ) ss ii Bromley et al., manuscript in preparation + ξξ SS SS

33 3D Fermi Insulator Clock Scaling up the Sr quantum clock: 1 million atoms (100 x 100 x 100 cells) Coherence 160 s Pauli Exclusion Principle 1 atom (clock) per site Precision 3 x Hz -1/2 Deborah Jin ( ) Quantum gas: Cornell, Ketterle, Wieman (2001)

34 Gravitational potential & gravity at once? Extreme spatial resolution & precision Jean Dalibard s grand challenge, Kastler Symposium 12/1/2016

35 Deeply Fermi degenerate 63, Sr atoms (6,300 per nuclear spin state); 8.1 nk T/T F = 0.05 SU(N) same scattering length for all spin states ħk ħk

36 A Fermi Gas Mott Insulator Clock xx yy zz Excitation fraction Clock laser frequency (khz)

37 Long atom-light coherence S. Campbell et al., Science 358, 90 (2017). 6s, 83 mhz Excitation fraction Laser detuning (Hz) Atom-Light coherence: 10 s Quality factor: 8 x 10 15

38 Spatial + Spectral resolution Marti et al., Phys Rev Lett 120, (2018). ππ/2 8 s ππ/2

39 Spatial + Spectral resolution Marti et al., Phys Rev Lett 120, (2018).

40 Snap shots of optical phase evolutions BB xx 1 Hz e g Allan Deviation min 1 x hours Average time (s)

41 Emergence of multi-atom interactions n = 5 n = 4 n = 3 n = 2 n = 1

42 So, let s go for the 160 s coherence time? We must reduce the lattice intensity! For g> atoms, lattice lifetime is >100 s e> Contrast g> Ramsey free evolution time (s) e> g> 813 nm 813 nm e> g>

43 A Fermi band/mott insulator clock a λ clock t 1 fermion 2 wells Lattice spacing = 813 nm / 2sin(θθ/2) a λ clock aa = a = λ clock tt 2 UU U 0 2 fermions 2 wells ee iiiiii = 1 Kolkowitz et al., Nature 542, 66 (2017); Bromley et al., Nature Phys. (2018).

44 Sr clock: the next systematic uncertainty collective dipoles Chang, Ye, Lukin, Phys. Rev. A 69, (2004). 1 mhz effect for a unity filled lattice (10-19 ) e> e ikr kr g> ω trap Collective dipolar couplings ( 1 S 0 3 P 1 : Bromley et al., Nature Comm., 2016) Real part: clock shift; Imaginary part: line broadening, super-radiance

45 Quantum Measurement Frontier Optical atomic clock Advanced materials Quantum information Advanced metrology Room-Temp. superconductor Loss-less electric grid Protein folding Drug design Entangled-states Quantum Simulators Quantum Cryptography

46 Sr optical clock advancing state-of-the-art S. Bromley T. Bothwell S. Kolkowitz J. Robinson L. Sonderhouse E. Oelker X. Zhang (Peking U.) T. Nicholson (MIT) M. Bishof (Argonne) B. Bloom (Intel) M. Martin (Sandia Nat l Lab) J. Williams (JPL) M. Swallows (AO Sense) S. Blatt (MPQ, Garching) A. Ludlow (NIST) Y. Lin (NIM) G. Campbell (JQI, NIST) T. Zelevinsky (Columbia U.) M. Boyd (AO Sense) J. Thomsen (U. Copenhagen) T. Zanon (Univ. Paris 6) S. Foreman (U. San Fran) X. Huang (WIPM) T. Ido (Tokyo NICT), X. Xu (ECNU) T. Loftus (AO Sense) S. Campbell R. Hutson G. E. Marti A. Goban A. M. Rey NIST, PTB, M. Holland, P. Julienne, M. Lukin, M. Safronova, R. Walsworth, S. Yelin, P. Zoller