Future of Quantum Science and Technology

Transcription

1 Future of Quantum Science and Technology Serge Haroche S.H &D.Wineland, 2012 Nobel in Physics Quantum theory has opened to us the microscopic world of particles, atoms and photons.and has given us the keys of modern technologies Yet, it obeys to strange laws which challenge our classical intuition, even if this strangeness - illustrated by the Schrödinger s cat tale - remains generally veiled at the macroscopic level Recent experiments controlling single quantum systems lead us to believe that the microscopic strangeness of quantum physics can be harnessed to develop new tools for communication, precise measurements and computing

2 Examples of mature Quantum technologies Computers Atomic clocks and GPS Lasers MRI scanners

3 The strangeness of the quantum State superpositions Two states at once Concepts illustrated by Schrödinger cat Entanglement Strange logic, at work in the microworld, usually veiled in macroscopic objects In order to observe directly these strange laws, manipulate single quantum systems (real or artificial atoms) These experiments open the way to exploiting directly quantum logic for practical applications

4 Five Berrylium ions in the lab of David Wineland (2000) Each atom is a 2 level quantum bit (qubit) which evolves as a superposition of 0 and 1 states and 14 and 30 Calcium ions in the lab of R. Blatt in Innsbruck ( ) 2 30 ~ 1 billion states! An atomic abacus for quantum information

5 A two dimension lattice of cold atoms (Immanuel Bloch lab in Garching, Germany)

6 Quantum information with artificial atoms Superconducting qubits: John Martinis group, UCSB 1 mm Google Two quantum dot qubits Yakobi group, Harvard

7 Perspectives of quantum technologies Quantum Simulations Arranging atoms in artificial structures simulates situations occurring in real materials at different scales One can control the atoms positions and the way they interact with each other, thus testing new physics Like a quantum chessboard in a game whose rules can be changed at will: an infinite number of quantum combinations which cannot be computed by classical machines Towards the synthesis of novel materials, with interesting properties (like superconductivity at room temperature)

8 Quantum cryptography Two entangled qubits Entanglement survives arbitrary separation (distances of hundreds of kms have been tested with entangled photons) As if two distant dices yielded same random result Allows two parties to share random numbers which nobody else can spy upon: secure quantum cryptography Technology demonstrated but progress remains to be made to increase the bit rate and preserve quantumness over large distances (quantum repeaters)

9 Quantum metrology Engineered quantum states can be much more sensitive to the variations of measurable quantities than classical «meters» Schrödinger cat state Novel clocks based on cold atoms reach a precision of 1 second over age of Universe, with still two or three orders of magnitude improvement to expect! Applications to GPS, geodesy, earth quakes predictions, gravitational wave detections Novel kinds of gyros, gravimeters, magnetometers and electrometers for applications to navigation, medical diagnosis, nanosensing

10 Quantum Computers Computers power and speed has exponentially increased since the 1950 s because the size of the bits has continuously decreased due to technological improvements The bit dimension will soon reach atom s size. The way to keep increasing the power is to exploit quantum effects (state superposition and entanglement) number of atoms per bit year Moore s law 1 atom per bit PenAum 4 22 nm transistor ~

11 The challenges of the quantum computer: a large «Schrödinger cat» tamed to compute very efficiently Decoherence which destroys state superposition (solution: quantum error correction) Find the suitable qubit candidates (real or artificial atoms) Find useful quantum algorithms Much more experimental and theoretical research required

12 It is hard to make predictions, especially about the future (Attributed to Niels Bohr) but one thing is sure: without basic research, novel technologies cannot be invented and the past teaches us that wonderful applications often emerge serendipitously from blue sky research Time has come for Europe to sustain a combined effort in basic and applied science to develop novel quantum technologies. The endeavour must be shared between academic institutions and private companies and young scientists should be attracted in it!