Mechanical resonators towards quantum limit: NEMS group together with NANO, THEORY, KVANTTI Mika Sillanpää assoc. prof., team leader Juha-Matti Pirkkalainen MSc, grad student Golam Kibria ChowdhuryMSc, grad student Jaakko Sulkko undergrad student Erno Damskäggundergrad student

Quantum limit of moving objects Mika Sillanpää, Low Temperature Laboratory  Optomechanics Cohadon, PRL 83, 3174 (1999). Gigan, Nature 444, 67 (2006). Kippenberg, Science 321, 1173 (2008).  c /(2  ~ Hz  m /(2  ~ 10 6 Hz  c /(2  ~ 10 6 Hz  m /(2  ~ 100 Hz

Circuit optomechanics Mika Sillanpää, Low Temperature Laboratory  Microwave resonator (”cavity”) with a movable boundary condition  Like an LC circuit with time-dependent capacitors

Circuit optomechanics Mika Sillanpää, Low Temperature Laboratory  High-impedance ”cavity”  Focused Ion Beam (FIB) cutting of narrow vacuum gaps (~10 nm)

Circuit optomechanics Mika Sillanpää, Low Temperature Laboratory  Mechanical microwave amplification  Coupling of mechanical resonators via cavity “quantum bus” F. Massel et al, Nature, 480, 351 (2011).

Cavity QED with phonons Mika Sillanpää, Low Temperature Laboratory  “Artificial atom” (transmon qubit) coupled to both photonic and phononic cavity

Cavity QED with phonons Mika Sillanpää, Low Temperature Laboratory  Phonon Stark shift  ultrastrong light-matter coupling

Cavity QED with phonons Mika Sillanpää, Low Temperature Laboratory  Electromechanical Rabi flops  Photon – phonon conversion  Motional sidebands  “Trapped-ion” experiments

Future Mika Sillanpää, Low Temperature Laboratory  Coupling of micromechanical resonators via ”cavity bus”  Coherent phonon transfer in time domain  Slowing down (and superluminal!) microwave pulses  Coupling to Josephson junction qubits  Increase coupling further  Create non-classical states of purely mechanical object  Circuit optomechanics with graphene  large zero-point amplitude x ZP ~ 1 pm  cool it near the ground state  Single-phonon strong coupling

Mika Sillanpää, Low Temperature Laboratory Mechanical resonators towards quantum limit:  Circuit optomechanics  Mechanical microwave amplifier  Quantum-limited operation predicted  Sideband cooling down to 1.8 phonon quanta  Hybridization of multiple phonons and a photon  phonon bus, creation of entanglement..?  Phonon QED  Motional sidebands of qubit spectral line  Sideband Rabi oscillations  Prospects  Creation of non-classical states of slowly moving objects  Long-lived quantum memory Mika Sillanpää, NEMS group