Joos, H. Zeh, C. Kiefer, D. Giulini, J. An excellent discussion on this point can be found in G. Heisenberg, Physics and beyond, encounters and conversations G. See: L. Boltzmann, Theoretical physics and philosophical problems , B.
MacGuinness, ed, Reidel, Dordrecht and Boston p — See, e. Such a string gives the impression of an identifiable individual, just as in the case of any object in our daily surrounding. Bell, Speakable and unspeakable in quantum mechanics Ref 5 Google Scholar. Wheeler andW. Gurney and E. In , three teams of researchers reported them happening in individual atoms suspended in space by electromagnetic fields. Since then, such jumps have been seen in various systems, ranging from photons switching between quantum states to atoms in solid materials jumping between quantized magnetic states.
In these experiments the jumps indeed looked abrupt and random — there was no telling, as the quantum system was monitored, when they would happen, nor any detailed picture of what a jump looked like. The key to the experiment is the ability to collect just about all of the available information about it, so that none leaks away into the environment before it can be measured.
Only then can they follow single jumps in such detail. Jumps between the energy states can be induced by absorbing or emitting a photon, just as they are for electrons in atoms. Devoret and colleagues wanted to watch a single artificial atom jump between its lowest-energy ground state and an energetically excited state. To watch the quantum jump, the researchers had to retain this coherence. To get around this problem, Devoret and colleagues employ a clever trick involving a second excited state.
The system can reach this second state from the ground state by absorbing a photon of a different energy. The researchers placed the superconducting circuit in an optical cavity a chamber in which photons of the right wavelength can bounce around so that, if the system is in the bright state, the way that light scatters in the cavity changes.
The key here, said Oliver, is that the measurement provides information about the state of the system without interrogating that state directly. In effect, it asks whether the system is in, or is not in, the ground and dark states collectively. That ambiguity is crucial for maintaining quantum coherence during a jump between these two states. In this respect, said Oliver, the scheme that the Yale team has used is closely related to those employed for error correction in quantum computers.
Again, this is done by not looking directly at the quantum bit in question but probing an auxiliary state coupled to it. The strategy reveals that quantum measurement is not about the physical perturbation induced by the probe but about what you know and what you leave unknown as a result.
The Yale team saw a series of clicks from the detector, each signifying a decay of the bright state, arriving typically every few microseconds. This stream of clicks was interrupted approximately every few hundred microseconds, apparently at random, by a hiatus in which there were no clicks. Then after a period of typically microseconds or so, the clicks resumed. However, in this case Devoret and colleagues could see something new.
Before each jump to the dark state, there would typically be a short spell where the clicks seemed suspended: a pause that acted as a harbinger of the impending jump. We demonstrate a close connection between the decoherent histories approach to quantum mechanics and the quantum state diffusion picture, for open quantum systems described by a master equation of … Expand.
The Strange Hi story of Particles and Waves. Abstract This is an attempt of a non-technical but conceptually consistent presentation of quantum theory in a historical context. While the first part is written for a general readership, Section 5 … Expand. Non-universality of dephasing in quantum transport. We investigate the influence of the environment on coherent quantum transport. While random processes with classical stochastic potentials can be treated in the concept of phase memory, this is not … Expand.
Quantum theory allows many more states for the objects described by it than we seem to encounter. Moreover, quantum dynamics especially the dynamics required to model measurements takes simple, … Expand.
There are no particles, there are only fields. Quantum foundations are still unsettled, with mixed effects on science and society. By now it should be possible to obtain consensus on at least one issue: Are the fundamental constituents fields or … Expand. Following a "collapsing" wave function. Quantum Discreteness is an Illusion. Their quantum … Expand.
Wave-function approach to dissipative processes: are there quantum jumps? In a recent Letter Dalibard and coworkers have presented an efficient method of computing the development of an open quantum system based on stochastic evolution of the state vector, in which quantum … Expand.
Dynamics of quantum correlations. Abstract The density matrix describing the state of a sybsystem of a physical system whose time dependence is assumed to follow a Schrodinger equation does not itself obey a von Neumann equation.
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