Quantum Nanomechanics
The group is part of the national Centre of Excellence – Quantum Technology Finland (QTF).
News
Aalto researchers awarded Physics World Breakthrough of the Year for macroscopic quantum entanglement
Aalto University Professor Mika A. Sillanpää, his team and collaborators at the University of New South Wales in Canberra, Australia, have won the Physics World 2021 Breakthrough of the Year. The prize was awarded for establishing quantum entanglement between a pair of macroscopic drumheads – two mechanical resonators that were tiny but still much larger than the subatomic particles that are usually entangled. The award has previously been given for the first direct observation of a black hole and for the detection of gravitational waves, which also received a Nobel Prize.
Novel quantum device design promises a regular flow of entangled electrons on demand
Quantum computer and many other quantum technologies rely on our ability to generate quantum entangled pairs of electrons. By dynamically controlling two quantum dots near a superconductor, researchers could time the extraction and splitting of entangled Cooper pairs from a superconductor.
Evading the uncertainty principle in quantum physics
New technique gets around 100-year-old rule of quantum physics for the first time
Physicist Mika A. Sillanpää wins a multi-million euro research grant to support work reconciling quantum mechanics and general relativity
The team is trying to solve a hundred-year-old mystery of physics with the help of small gold spheres and extremely low temperatures. The observation of tiny gravitational forces between vibrating spheres may solve the mystery.
Group leader
Prof. Mika Sillanpää
Entangled mechanical oscillators
Entanglement is perhaps the most intriguing feature of quantum mechanics. It allows objects to affect each other across arbitrary distances without any direct interaction, defying both classical physics and our common-sense understanding of reality. Entanglement is now commonly observed in experiments with microscopic systems such as light or atoms, and is also the key resource for quantum technologies such as quantum computation, cryptography and measurement.
Quantum entanglement is, however, extremely fragile, and it will disappear if the entangled particles interact with their surroundings, through thermal disturbances, for example. For this reason, entanglement between the motion of macroscopic objects has long been an elusive goal.
In recent works we created and stabilised entanglement between the center-of-mass motion of two drumhead resonators. The drumheads, 15 micrometer in diameter, are capacitively coupled to a single microwave "cavity" formed by a superconducting circuit. By driving the system with suitable microwave fields, we cool the thermal disturbances and bring the drumheads to a steady state where they are entangled indefinitely. Our work qualitatively extends the range of entangled physical systems and has implications for quantum information processing, precision measurements and tests of the limits of quantum mechanics.
- Quantum mechanics–free subsystem with mechanical oscillators, Science 372, 625-629 (2021).
- Perspective: H.-K. Lau, A. Clerk, Macroscale entanglement and measurement, Science 372, 570-571 (2021).
- Stabilized entanglement of massive mechanical oscillators, Nature 556, 478 (2018)
- News & Views: Andrew Armour, "Entangled vibrations in mechanical oscillators", Nature 556, 478 (2018)
- Press release
Quantum Backaction Evading Measurement of Collective Mechanical Modes
The standard quantum limit constrains the precision of an oscillator position measurement. It arises from a balance between the imprecision and the quantum backaction of the measurement. However, a measurement of only a single quadrature of the oscillator can evade the backaction and be made with arbitrary precision. We have demonstrated quantum backaction evading measurements of a collective quadrature of two mechanical oscillators, both coupled to a common microwave cavity. The work allows for quantum state tomography of two mechanical oscillators, and provides a foundation for macroscopic mechanical entanglement and force sensing beyond conventional quantum limits.
-
Quantum Backaction Evading Measurement of Collective Mechanical Modes, Phys. Rev. Lett. 117, 140401 (2016).
Magneto acoustics
In a new research effort, we integrate magnetic materials with nano- and micromechanical devices to advance fundamental science and to obtain new functionalities that can lead to disruptive technologies. We study strain-mediated interactions between magnons and phonons in magnetic mechanical oscillators. The hybrid potential is provided by magnetostriction, which couples mechanical strain to magnetization. This activity can be regarded as a strong analog to cavity optomechanics, with magnons replacing the electromagnetic cavity.
Optomechanics with macroscopic quartz resonators
We observe optomechanical physics in a truly macroscopic oscillator close to the quantum ground state. As the mechanical system, we use a mm-sized piezoelectric quartz disk oscillator. Its motion is coupled to a charge qubit which translates the piezo-induced charge into an effective radiation–pressure interaction between the disk and a microwave cavity. The work opens up opportunities for macroscopic quantum experiments.
-
Optomechanical measurement of a millimeter-sized mechanical oscillator approaching the quantum ground state, New J. Phys. 19 103014 (2017).
-
High-Precision Displacement Sensing of Monolithic Piezoelectric Disk Resonators Using a Single-Electron Transistor, J. Low Temp. Phys. 191, 316 (2018).
