Spin-Squeezing and Non-Classical States

Spin-Squeezing and Non-Classical States

Concepts for the generation, manipulation and applications of squeezed and entangled atomic ensembles.

Contributions to QuantumFrontiers

  • Development of concepts for the generation, manipulation and detection of spin-squeezed and entangled many-body states.
  • Exploration of methods for their transfer to external degrees of freedom.
  • Devise applications for entanglement-enhanced sensitivities in frequency, magnetic field, and inertial sensing.
  • Investigate entangled states for tests of fundamental physics: fundamental sources of decoherence and coupling of quantum objects to general relativity.

Collaborative Innovation

  • Collaboration between theory and experiments on spinor Bose-Einstein condensates (Santos LUH, Klempt LUH/DLR-SI)
  • Collaboration on momentum entanglement for atom interferometers (Rasel LUH, Klempt LUH/DLR-SI)
  • Collaboration on entanglement-enhanced metrology (Smerzi, Santos LUH)
  • Entanglement-enhanced atom source in microgravity (Rasel LUH, Klempt LUH/DLR-SI)

Scientific Output

  • Publications

    Anders F, Idel A, Feldmann P, Bondarenko D, Loriani S, Lange K et al. Momentum Entanglement for Atom Interferometry. Physical Review Letters. 2021 Oct 1;127(14). 140402.

    Corgier R, Gaaloul N, Smerzi A, Pezzè L. Delta-Kick Squeezing. Physical Review Letters. 2021 Oct 29;127(18). 183401.

    Feldmann P, Klempt C, Smerzi A, Santos L, Gessner M. Interferometric Order Parameter for Excited-State Quantum Phase Transitions in Bose-Einstein Condensates. Physical review letters. 2021 Jun 10;126(23). 230602.

    Kaubruegger R, Vasilyev DV, Schulte M, Hammerer K, Zoller P. Quantum Variational Optimization of Ramsey Interferometry and Atomic Clocks. Physical Review X. 2021 Dec 6;11(4). 041045.

    Vitagliano G, Fadel M, Apellaniz I, Kleinmann M, Lücke B, Klempt C et al. Detecting Einstein-Podolsky-Rosen steering and bipartite entanglement in split Dicke states. 2021 Apr 12.

    Canuel B, Abend S, Amaro-Seoane P, Badaracco F, Beaufils Q, Bertoldi A et al. ELGAR: a European Laboratory for Gravitation and Atom-interferometric Research. Classical and Quantum Gravity. 2020 Oct 28;37(22). 225017.


    Chabuda K, Dziarmaga J, Osborne TJ, Demkowicz-Dobrzański R. Tensor-network approach for quantum metrology in many-body quantum systems. Nature Communications. 2020 Jan 14;11(1):250. 250.


    Chu A, Will J, Arlt J, Klempt C, Rey AM. Simulation of XXZ spin models using sideband transitions in trapped bosonic gases. Physical review letters. 2020 Dec 7;125(24). 240504.


    Lisdat C, Klempt C. Quantum engineering for optical clocks. NATURE. 2020 Dec 16;588(7838):397-398.

    Schulte M, Lisdat C, Schmidt PO, Sterr U, Hammerer K. Prospects and challenges for squeezing-enhanced optical atomic clocks. Nature Communications. 2020 Nov 24;11(1). 5955.

    Schulte M, Martínez-Lahuerta VJ, Scharnagl MS, Hammerer K. Ramsey interferometry with generalized one-axis twisting echoes. Quantum. 2020 May 15;4:268-286.

    ELGAR. Technologies for the ELGAR large scale atom interferometer array. 2020 Jul 8.

    Hüper A, Pür C, Hetzel M, Geng J, Peise J, Kruse I et al. Preparation of mesoscopic atomic ensembles with single-particle resolution. 2019 Dec 11.

    Kristensen MA, Christensen MB, Gajdacz M, Iglicki M, Pawłowski K, Klempt C et al. Observation of Atom Number Fluctuations in a Bose-Einstein Condensate. Physical Review Letters. 2019 Apr 26;122(16):163601. 163601.

    Pezzè L, Gessner M, Feldmann P, Klempt C, Santos L, Smerzi A. Heralded Generation of Macroscopic Superposition States in a Spinor Bose-Einstein Condensate. Physical Review Letters. 2019 Dec 31;123(26). 260403.


    Tino GM, Bassi A, Bianco G, Bongs K, Bouyer P, Cacciapuoti L et al. SAGE: A proposal for a space atomic gravity explorer. European Physical Journal D. 2019 Nov;73(11). 228.


TG Members

  • Involved Members and their Relevant Expertise
    Members Institution Relevant Expertise
    Carsten Klempt, Leader LUH / DLR-SI Quantum Atom Optics
    Bernd Meyer-Hoppe LUH Quantum Optics with Non-classical States of Matter
    Mareike Hetzel LUH Quantum Optics with Non-classical States of Matter
    Martin Quensen LUH Quantum Optics with Non-classical States of Matter
    Wolfgang Ertmer LUH/DLR-SI Ultracold quantum gases and precision metrology
    Luis Santos LUH Theory of Dynamics of Manybody Quantum Systems
    Luis Peña Ardila LUH Excited state phase transitions for the generation of entanglement
    Ernst M. Rasel LUH Quantum sensors
    Christian Schubert LUH/DLR-SI Atom interferometry
    Dennis Schlippert LUH Atom interferometry
    Naceur Gaaloul LUH Theory of many-body physics and atom interferometry
    Piet O. Schmidt PTB / LUH Squeezing and non-classical states in trapped ions, precision metrology
    Christian Lisdat PTB Frequency metrology
    Klemens Hammerer LUH Theory of quantum optics, coupling to general relativity