Kindle Notes & Highlights
by
Nick Herbert
Read between
February 28 - December 27, 2022
hidden-variable models of reality,
All we have to do is precisely measure an attribute which is conjugate to the live/dead attribute; the uncertainty principle does the rest.
CAN PHASE RANDOMIZATION COLLAPSE THE WAVE FUNCTION?
It is not difficult to find mechanisms for phase randomization inside measuring devices. Italian physicists Antonio Daneri, Angelo Loinger, and Giovanni Maria Prosperi show that the thermodynamics of large bodies can randomize phases.
Russian physicist Dmitri Blokhintsev shows that the process of amplification, which makes a quantum process visible to human eyes, will inevitably randomize quantum phases. Others blame phase randomization on the irreversible process involved in making a record.
Physicists H. Dieter Zeh and Wojciech H. Zurek show that interactions with the environment are continually randomizing the phases of macroscopic objects. In their view, cats and photon counters don’t ...
This highlight has been truncated due to consecutive passage length restrictions.
This collapse location is consistent with the results that for each photon only one symbol (Up or Down) is typed on the output tape, but such a premature collapse will not agree with another experiment we can do which determines whether a photon takes one path or two.
Does the wave function collapse when the photon excites a phosphor molecule? Most physicists would argue that it does not.
it’s unlikely that the wave function collapses at the lenses.
this experimental method depends on the fact that the waves in each path have well-defined phases.
when waves add with random phases their interference pattern disappears.
We recall from Chapter 5 that ordinary waves added with definite phases do not conserve energy (amplitude squared) everywhere, but show local regions of energy surplus and deficit. However, when the waves are randomized energy is conserved everywhere: energy in one beam adds like ordinary arithmetic to energy in the other beam.
The same thing happens to randomized quantum waves, but here probability (quantum amplitude squared) takes the place of energy in ordinary waves.
when these waves are randomized, probability is conserved everywhere: probability in one beam adds like ordinary arithmetic to probability in the other beam. In other words, when a quantum wave’s phase is randomized, its corresponding probabilities combine exactly like classical dice probabilities.
quantum and classical probabilities are conceptually the same.
wave function collapse and convert a situation in which a quon take both paths (quantum ignorance) to a situation in which it takes only one (classical ignorance).
The spectral area code (Heisenberg uncertainty principle) is another wave property that remains valid whether phases are orderly or not.
APPENDIX: CALCITE, A CRYSTAL THAT SPLITS PHOTONS
The key to calcite’s behavior is its optic axis—a special direction, indicated by an arrow in Fig. 8.1, that runs through the crystal. Light polarized parallel to this axis travels through the crystal normally. Light polarized at right angles to the optic axis takes a deviant route—the extraordinary way. If the optic axis is oriented vertically, vertically polarized photons take the ordinary path (up), horizontally polarized photons go the extraordinary way (down).
theory, the calcite crystal is a window into the microcosm: its double beam is indicative of the two-valuedness of the photon’s polarization attribute.
Four Quantum Realities
Quantum Reality #1: The Copenhagen interpretation, Part I. (There is no deep reality.)
A pragmatist would refuse on principle to comment on the existential status of an unmeasured electron’s attributes.
They base their conclusions about an unseen quantum reality not on some abstract philosophical principle applicable in all cases but on the specific structure of quantum theory itself. Some
Quantum uncertainty is not tied to one particular attribute but slides from attribute to attribute as we change our minds about what to measure.
uncertainty was attributed to an unavoidable disturbance of the quantum system by measurement—a disturbance which could neither be minimized (because Planck’s constant enforces a minimum action exchange) nor calculated (because of quantum randomness).
A second argument against the disturbance model of measurement is the existence of “Renninger-style measurements”—measurements in which information is gained about a system through the absence of a detection event.
“nothing happens.”
As an example of a Renninger-style measurement, consider a quantum system that possesses just two possibilities—for instance, light from a distant star which can bounce off either mirror A or mirror B of a stellar interferometer.
Bohr’s explanation of the slipperiness of quantum attributes is that such attributes do not belong to the quon itself but reside in “the entire measurement situation”—a phrase Bohr was particularly fond of. When we measure a certain attribute, we should not imagine that the electron actually possesses this attribute. Electrons possess no attributes of their own. An electron’s so-called attributes are really relations between the electron and its measuring device and do not properly belong to either.
The question is, do attributes of this kind truly belong to the quon in question or do they partly belong to the M device—to the analyzer prism, for instance?
Electrons do not possess position, momentum, or any other dynamic attributes. These so-called attributes are not intrinsic properties of quantum systems but manifestations of “the entire experimental situation.”
According to Bohr, “Isolated material particles are abstractions, their properties being definable and observable only through their interaction with other systems.”
The quantum world is not made up of objects. As Heisenberg puts it, “Atoms are not things.”
This does not mean that the quantum world is subjective. The quantum world is as objective as our own: different people taking the same viewpoint see the same thing, but the quantum world is not made of objects (different viewpoints do not add up). The quantum world is objective but objectless.
An example of a phenomenon which is objective but not an object is the rainbow. A rainbow has no end (hence no pot of gold) because the rainbow is not a “thing.” A rainbow appears in a different place for each observer—in fact, each of your eyes sees a slightly different rai...
This highlight has been truncated due to consecutive passage length restrictions.
An electron’s attributes do not belong to the electron itself but are a kind of illusion produced by the electron plus “the entire experimental arrangement.”
“Scientists of the late twenties, led by Bohr and Heisenberg, proposed a conception of nature radically different from that of their predecessors … Their theoretical structure did not extend down and anchor itself on fundamental microscopic space-time realities. Instead it turned back and anchored itself in the concrete sense realities that form the basis of social life. This radical concept, called the Copenhagen interpretation, was bitterly challenged at first but became during the thirties the orthodox interpretation of quantum theory, nominally accepted by almost all textbooks and
...more
Bohr treats M devices in a special way. He does not represent an M device as a possibility wave but considers it a solid actuality. By objectifying the M device, he can account for the “ordinariness” of quantum fact and avoid such monstrosities as Schrödinger’s live/dead cat which arise if you believe that the same quantum rules hold for cats and electrons. Throughout his career Bohr continued to emphasize the “classical style” of existence enjoyed by ordinary objects.
Bohr recognizes here that the form of every quantum fact is identical to the form of every prequantum fact—that is, nothing special. It’s an unchangeable fact of life that our direct experience of an electron (flash-on-a-screen) is no more mysterious than our direct experience of cats and rainbows.
This endless procession of measuring devices measuring one another is called “von Neumann’s paradox of infinite regress.” Von Neumann’s paradox results from the assumption of special non-quantum entities—measuring devices—while at the same time we know that such devices cannot really be special.
Thus, in the Copenhagen view quantum theory can explain with great exactitude the behavior of atoms, but is powerless to cope with the attributes of cats and apples in their roles as unscrutinized parts of “the entire experimental situation”.
Quantum Reality #2: The Copenhagen interpretation, Part II. (Reality is created by observation.)
“No elementary phenomenon is a real phenomenon until it is an observed phenomenon,” Wheeler maintains. Perhaps this quantum reality should be called the “Austin interpretation of quantum theory” in honor of Wheeler’s institute.
Every physicist upholds the absolute existence of matter—electrons, photons and the like—as well as certain of matter’s static attributes. However, observer-created reality physicists do believe that dynamic attributes—position and momentum, for instance—do not exist until they are actually observed.
Quantum Reality #3: Reality is an undivided wholeness.
Bohr’s notion that quantum attributes are not localized in the quon itself but reside (like the position attribute of a rainbow) in “the entire experimental arrangement.”
“phase entanglement.”
The concept of “phase entanglement” arises when we consider how two or more interacting quons acquire their attributes.
The reason that quantum waves become phrase-entangled and ordinary waves don’t is that quantum waves do not make their home in ordinary three-dimensional space but in a place called configuration space.
