In classical physics, interactions appear to be of the form of cause and effect, as in Newton’s second law is: F = dp/dt. The force F governs the interaction and dp/dt is the effect. In quantum mechanics, there is a probability for an impulse hit interaction by a particle given by exp(ipx) within a wavelength region of size hbar/p. As a result, instead of an interaction occurring within dx->0, the particle itself dictates an interaction region of the size hbar/p. Consequently, in a 2-slit interaction, the slits should be about a wavelength hbar/p apart. In classical physics, an interaction occurs within the interaction region (dx->0), but in the 2-slit case the interaction region includes the space from the first slit to the second, so to ask: What is happening as the particle interacts within this region? means that a particle can pass through one slit and inteact with the other, or it can interact with the slit through which it passes. The interaction region is the smallest region in which the interaction occurs (as if it were a black box). The particle physically passes through one slit or the other, but interacts either way with both slits probabilisitcally because otherwise the interaction region would only be one slit or the other contradicting the probabilistic range hbar/p of interaction. As a result, a two-slit calculation is really a calculation of an interaction within an hbar/p region including both slits. This interaction is probabilistic due to the exp(ipx) interaction hit nature of the particle and so it is the particle which dictates the interaction to a large degree. The fact that the particle must pass through one slit or the other, together with a probabilistic interaction over the hbar/p region means that two key notions are at work, one being the physical location of the particle (passing through one slit or the other) which governs how the probabilistic interaction (due to the particle) operates. In particular, one draws two parallel rays, one from the center of each slit towards a fixed point on a screen far away. The interaction is based on the exp(ipx) probabilistic interaction of the particle and the separation of the two slits because the particle interacts with both as it passes through only one. In other words, reality is not simply based on what one can measure during an interaction. The fact that one does measure through which slit the particle passes does not mean that the positions of the slits cannot stil helpl lead to determinate statements such as zero particles arrive at certain x points on the screen. The slit separation is part of the physical reality of the problem. (Note: there is also diffraction from the two edges of each slit, i.e. diffraction, which follows the same ideas and so one has a combination of diffraction from each slit together with interference.) As a result, we suggest that one consider the entire region from one slit to the other as a quantum interaction region similar to the dx->0 used in Newtonian mechanics. Quantum mechanics then provides a probabilistic, not deterministic, descripition of possible interactions and their probability weights, unlike the cause (force) and effect (deterministic change in p of the particle) of Newtonian mechanics. The exp(ipx), hbar/p gradation form of probability, allows for probabilities to add or subtract at different x points. The walls of the 2-slit apparatus are linked with probabilistic momentum angle changing, with each angle having the same probability (uniform distribution), but otherwise much of the interaction is dictated by the particle, unlike in Netwonian mechanics. For a V(x) = Sum over i Vk exp(ikx), both exp(ipx) and exp(ikx) are one a similar footing.
In classical physics, interactions appear to be of the form of cause and effect, as in Newton’s second law is: F = dp/dt. The force F governs the interaction and dp/dt is the effect. In quantum mechanics, there is a probability for an impulse hit interaction by a particle given by exp(ipx) within a wavelength region of size hbar/p. As a result, instead of an interaction occurring within dx->0, the particle itself dictates an interaction region of the size hbar/p. Consequently, in a 2-slit interaction, the slits should be about a wavelength hbar/p apart. In classical physics, an interaction occurs within the interaction region (dx->0), but in the 2-slit case the interaction region includes the space from the first slit to the second, so to ask: What is happening as the particle interacts within this region? means that a particle can pass through one slit and inteact with the other, or it can interact with the slit through which it passes. The interaction region is the smallest region in which the interaction occurs (as if it were a black box). The particle physically passes through one slit or the other, but interacts either way with both slits probabilisitcally because otherwise the interaction region would only be one slit or the other contradicting the probabilistic range hbar/p of interaction. As a result, a two-slit calculation is really a calculation of an interaction within an hbar/p region including both slits. This interaction is probabilistic due to the exp(ipx) interaction hit nature of the particle and so it is the particle which dictates the interaction to a large degree. The fact that the particle must pass through one slit or the other, together with a probabilistic interaction over the hbar/p region means that two key notions are at work, one being the physical location of the particle (passing through one slit or the other) which governs how the probabilistic interaction (due to the particle) operates. In particular, one draws two parallel rays, one from the center of each slit towards a fixed point on a screen far away. The interaction is based on the exp(ipx) probabilistic interaction of the particle and the separation of the two slits because the particle interacts with both as it passes through only one. In other words, reality is not simply based on what one can measure during an interaction. The fact that one does measure through which slit the particle passes does not mean that the positions of the slits cannot stil helpl lead to determinate statements such as zero particles arrive at certain x points on the screen. The slit separation is part of the physical reality of the problem. (Note: there is also diffraction from the two edges of each slit, i.e. diffraction, which follows the same ideas and so one has a combination of diffraction from each slit together with interference.) As a result, we suggest that one consider the entire region from one slit to the other as a quantum interaction region similar to the dx->0 used in Newtonian mechanics. Quantum mechanics then provides a probabilistic, not deterministic, descripition of possible interactions and their probability weights, unlike the cause (force) and effect (deterministic change in p of the particle) of Newtonian mechanics. The exp(ipx), hbar/p gradation form of probability, allows for probabilities to add or subtract at different x points. The walls of the 2-slit apparatus are linked with probabilistic momentum angle changing, with each angle having the same probability (uniform distribution), but otherwise much of the interaction is dictated by the particle, unlike in Netwonian mechanics. For a V(x) = Sum over i Vk exp(ikx), both exp(ipx) and exp(ikx) are one a similar footing.
Classically, probability is considered in terms of the number of possible outcomes. For example, a die toss has six possible outcomes and a coin toss, two. Probability calculations make use of probabilities and hence of the total number of possible outcomes. Thus, they are not deterministic calculations which follow “what happens” as in Newtonian mechanics. We suggest that if free particle quantum mechanics is probabilistic, it must also involve the notion of possible outcomes in an experiment and not represent a deterministic approach. We suggest, however, that something interesting applies to quantum mechanics because we have suggested that free particle quantum mechanics arises from the Lorentz invariant A = -Et+px. We note that there exist x,t trajectory points which follow x=vt. We also note, however, that one may introduce the idea of intervals dx, dt (because Newton’s dx→0, dt→0 is an idealization) and that A is unchanged for x,t and x+hbar/p , t+hbar/E. In other words, we suggest that there are intervals with probability about each x,t trajectory point. A trajectory point is associated with deterministic physics, but probability about this point is not. In other words, one has a kind of hybrid probability scheme. Thus, exp(ipx) and exp(-iEt) really represent fluctuation probabilities about a trajectory point x and t. These ranges of possible x and t fluctuations about a trajectory point x,t allow for further probability to occur in certain interactions. We consider two examples. The first is 2-slit interference which involves a deterministic particle moving along a straight line towards a 2-slit mechanism perpendicular to its path. At the 2-slit apparatus, one considers a probabilistic calculation as the uncertainty in x, i.e. dx=hbar/p allows for possible interaction with both slits. This involves considering all possible outcomes (i.e. motion through one slit or the other which is a classical situation), but exp(i p dot r1) and exp(i p dot r2) “sit on top” of these trajectories at the 2-slit apparatus and one has interference of the probabilities linked with each classical possible outcome. Thus, there are two sets of probabilities which are intertwined, the probability range hbar/p for each path and the two possible paths which have equal probability. One must consider the possible outcomes for both sets together. We suggest that a similar analysis applies to the case of 1-D reflection-refraction for x=0 at an n1-n2 index of refraction junction. Thus, we suggest that a deterministic free particle with x=vt may encounter probabilistic interaction situations, such as a two-slit apparatus or an n1-n2 index of refraction junction. These are probabilistic only because there is a probability fluctuation scheme in x associated with each deterministic x point. It is this probability which allows for a second probability to arise due to interaction with the slits or at the 1-D n1-n2 junction. In such a case, one must consider all possible outcomes which means that one does not only consider the exp(ipx) type probabilities, but also those linked with the physical interaction, i.e. two possible paths, one from each slit, or an incident, reflected and refracted photon at x=0 (n1-n2 junction). It is a combination of all possible paths which must be used in calculations. We thus suggest that even though there is a sense of determinism, i..e free particles move as x=vt and these exist in the 2-slit case and the 1-D reflection-refraction case, in a probabilistic calculation one must consider all probabilistic outcomes consistent with these. Thus, quantum mechanical calculations are true probabilistic calculations in the sense that they involve all possible outcomes in an analysis.
In Part 1, we argued that the consideration of all possible outcomes is a defining idea of a probabilistic calculation. We then argued that in free particle quantum mechanics there were two sets of outcomes, one driving the other. In particular, a single particle moves as x=vt, but at each x,t point, one has interaction uncertainty/fluctuations of dt and dx linked with exp(-iEt) and exp(ipx). As a result, in a 2-slit interference problem, exp(ipx) (a probability linked with possible positional fluctuations about x) leads to a further probability of interacting with both slits. The two sets of outcomes must be considered, i.e. exp(i p dot r1) + exp(i p dot r2), where r1 is a vector from the center of the first slit to a point on a screen far away, and r2, a vector from the center of the second slit to the same screen point. We also considered the case of reflection-refraction from an n1-n2 index of refraction junction. The point is that these two cases are clearly probabilistic, i.e. not deterministic at all. Here we consider two different scenarios which have the appearance of a deterministic result, but are actually probabilistic and so linked with all possible outcomes, i.e. an average over these which must be understood as an average (as in classical probability). The first is a single particle bound state and the second, transmission through a potential wall. In the bound state case, the analogue is a Newtonian bound state and in fact between the classical turning points KEave(x) + V(x) = E in the probabilistic case which exactly matches the classical one. One is, however, dealing with an average KEave(x) = -1/2m d/dx d/dx W/ W, where W=Sum over p a(p)exp(ipx), it involves all possible outcomes and is not a physical state. Given the similarity to a deterministic problem there is a danger of not considering the quantum bound calculation as a probabilistic one. In the quantum single particle case, one may be surprised by tunneling, but the quantum probabilistic scenario is one in which all possible interaction outcomes are considered together (as is required by probability) and so one cannot possibly ignore interactions linked to a particle entering or leaving the potential region. Furthermore, it is only KEave(x) which equals the classical result and so E which is single value in the classical case, is linked to an average value in the quantum case, i.e. a particle may have a p such that pp/2m is not zero at the classical turning point. Only KEave(x) =0 at this point. An interesting feature is that a probabilistic calculation applies to a single particle run (which only produces one outcome). One, however, cannot measure the full probability associated with a problem without making a very large number of measurements.
In Part 1, we argued that the Heisenberg uncertainty principle (standard deviation p) * (standard deviation x) >= hbar/2 only applies when a measurement (i.e. interaction) has occurred. Otherwise, the notion of standard deviation does not exist. Thus, if one has a Gaussian wavepacket, it is the measuring device which has created it and constrained is standard deviations of momentum and position. A free particle, which has not been measured, is described by exp(-iEt+ipx), as argued in Part 1, and not by a wavepacket. Here we ask: How does one interpret a wavepacket calculation? In (1), we argued that exp(-iEt) is a free particle energy conserving probability and exp(ipx), a momentum conserving one. Then, a sum of exp(ipx - iEt) represents an OR situation in probability theory. There is superposition and so one obtains a weighting of possible outcomes which is the probabilistic interpretation of the scenario. If one considers two slit interference, the viewpoint is the same. exp(ipx) is a probability which allows for momentum hits of p in a range of dx=hbar/p outside the center-of-mass, which follows x=vt. This built-in stochasticity of impulse delivery leads to the notion that probabilistically, a particle may interact with both slits if their separation is about hbar/p. One writes an OR probability statement: W(x)= exp(i p dot r1) + exp(i p dot r2), where r1 is the position vector from the center of slit 1 to a point far away on a screen, and r2, a vector from the center of slit 2 to the same point. The result, W*(x)W(x) is a probabilistic expression which describes the possible outcomes probabilistically. (1). Seen in this way, the Gaussian wavepacket should be interpreted in a similar manner and not as a physical description of the particle which moves freely. A single bound state in a potential V(x) is localized by a potential and one may consider only OR cases of exp(ipx), i.e W(x) = Sum over p a(p)exp(ipx). In the measurement case, there is no quasi-permanent localization and one uses a linear superposition of exp(-iEt+ipx)s. Nevertheless for a Gaussian wavepacket, two probability distributions describing possible outcomes are created. One has W*(x)W(x)= exp(- (x-u)(x-u) / (2 sigma(t) sigma(t))) where sigma is the x standard deviation. In addition, W(x) = Sum over p a(p) exp(ipx), leading to a momentum outcome distribution of a*(p)a(p). As written, sigma(t) for x which means that the Gaussian is expanding. We called this unphysical if one considers the wavefunction as representing a description of a single physical entity (2) at times beyond t=0. Like in the 2-slit case, we argue that it represents an outcome distribution. Thus, one would not consider any more time values than t=0, at which time the measurement is completed. An exp(-iEt+ipx), describing a free particle, is measured by a specific device which creates the Gaussian form and gives it a specific standard deviation in space and momentum. The measurement is then done and W*(x,t=0)W(x, t=0) represents the possible outcome positions of the particle at t=0 (i.e. probabilities for x portions of a phase shift). The momentum distribution yields possible p outcome values. As soon as the measurement is finished, the particle moves as exp(-iEt+ipx), with p being probabilistically linked to a*(p)a(p) (a Gaussian as well), where W(x,t) = Sum over p a(p)exp(-iEt+ipx).If one has a second measuring device which creates a tiny momentum standard deviation, one would be able to carry out experiments which would determine roughly the standard deviation of p created by the first measuring device. Furthermore, one would be able to measure phase shifts as well by comparing a free particle measured by a device with a tiny p standard deviation and a large x one with free particles which were not measured.
In Part 1, we argued that P(x)dx=dx/L (where L is an arbitrary length) applies to a particle at rest. If one views such a particle from a frame moving at constant -v, it is moving. We argued that in such a case, the relevant probability is not simply linked to the position x, but also to the momentum p at x because this delivers an impulse hit. In particular, probability is presumably to be used in a physical problem with interactions and probability and a dynamical particle requires a dynamical probability describing both x,t and E,p. This led to exp(-iEt+px) which actually predicts intervals in space hbar/p and time hbar/E. In other words, a probabilistic view point leads to these results. Here, we ask the question: What if one simply wishes to use deterministic physics to describe a moving particle? After all, Newtonian mechanics is deterministic and one does not really need to focus on P(x)=1/L or its modification for a moving particle. In such a case, a particle moving with constant v (starting at x=0, t=0) is described by x/t=v both in Newtonian mechanics and special relativity. There is no uncertainty in x and t here which begs the question: Why does it appear in the probabilistic formalism of Part 1? In particular, exp(-iEt+ipx) derived in Part 1 implies physical regions: dx = hbar/p and dt=hbar/E and these seem to be absent in x/t=v and this is a problem. We suggest that a probabilistic approach is buried in the Lagrangian formalism which leads to the result d/dt v = 0, i.e describes the particle’s motion in space. This motion is actually x/t=v, but this equation only presents a subset of the description of a particle that is moving with constant speed, even in a deterministic Lagrangian/Action approach. We have already pointed this out in (1). We briefly explain it again here, but the real question is why does one need to consider the Lagrangian in order to describe x/t=v? In other words, the probabilistic approach associated with v=x/t only emerges in the Lagrangian formalism using a relativistic action Lt = -Et+px, with x/t=v. Ignoring the action and Lagrangian leads to an absence of hbar/p and hbar/E and one is only concerned with x/t=v. We note that the Lagrangian is primarily linked to the result: p = dL/dv partial and so argue that one is not simply interested in motion (x/t=v), but also in interaction because p is associated with an impulse hit. Thus, the Lagrangian approach is more than simply a mechanism which describes x,t motion, it is associated with p and E (through Hamiltonian = E = pv-L.) Using the Lagrangian approach suggests that it does not suffice to consider x and t by themselves when p and E are present. One must consider all four variables x,t,E,p which is the same point made in Part 1. The physics of the problem dictates that it is not enough to simply think in terms of x,t,v. The Lagrangian approach, which is constructed to ultimately yield x/t=v, when written in terms of E, p, i.e. Lt = -Et+px demonstrates uncertainty in x, hbar/p and t, hbar/E as shown in (1). This uncertainty must then be written in terms of a probability which is Lorentz invariant and leads to exp(-iEt+ipx). The point is that one would not even consider a probability if one did not consider E,p and x,t together as a complete treatment of a moving particle. In other words, x/t=v is an incomplete description of the state of a particle moving with constant speed, even in a deterministic framework.. At first this might seem surprising, but it is well known that energy and p are linked to interactions. In special relativity, one does not consider x,t,v alone and then compute p and E from these, but considers four vectors and Lorentz invariant equations. It is possible to create a Lorentz invariant equation involving all four state variables x,t,E,p and it turns out that this is the relativistic Lagrangian which describes motion, so this approach is more general than simply stating x/t=v. Thus, delta x = hbar/p and delta t= hbar/E appear in both the probabilistic approach of Part 1 and the deterministic one of the Lagrangian used here.
In Part 1, we tried to create a toy model involving a rotating-translating coin. We examined what kind of interaction is needed to create a typical 2-slit interference pattern. Here we examine a physical object, namely a photon, which has a built-in periodic cycle for its electric and magnetic fields. These are perpendicular and in plane perpendicular to motion and both change as cos(-Et/hbar + px/hbar). We point out that the electric and magnetic fields are both real, they are not described by exp(-iEt+ipx) and furthermore, they are deterministic, not probabilistic. We try to see how such a picture can lead to quantum two slit interference. Basically, we argue that if one only considers the electric field, long range interactions from atoms around both slits interact with a photon heading towards the center between the slits. As a result, the physical interaction must involve both slits, but one has no idea through which slit the photon passes. There is probability in the problem, but at the same time interactions with both slits before the photon passes through and also after. One needs a model which captures both the notion of probability and interaction with both slits. For probability this should be an OR situation (one slit or the other), but it cannot be the usual classical probability scheme which implies that moving through one slit only involves interaction with that slit. Interactions with both slits occur. This seems like a contradiction because one applies OR probability to one slit or another. Given that the interaction with the electric field occurs in a periodic manner cos(-Et+px) hbar=1, we suggest that exp(-iEt+ipx) with its modulus of 1 captures the idea that any electric field position as the same probability, but that there is periodic motion linked with interaction in space. . As a result, one may keep the mathematical notion of an OR probability scheme by introducing an interacting probability exp(ipx). This means that the probaiblities from each slit in the OR (add) scheme interfere or interact which is what is required because an interaction with both slits occurs. exp(ipx) captures the periodicity and also enforces conservation of momentum (exp(ip1x)exp(ip2x) = exp(I (p1+p2)x) and it seems that this is the only information needed.
Traditional quantum mechanics calculates a probability in space through W*(x)W(x) for a time-independent wavefunction W(x) = Sum over p a(p)exp(ip dot r). We argue that this probability is created at the interaction region and indicates a probability for outcomes. In particular, given a 2-slit problem, one calculates W(r) = exp( i p dot r1) + exp(i p dot r2), where r1 and r2 are vectors from the center of each slit to the same point on a screen far away. W(r)*W(r) then represents the probability for particles to arrive at various points on the screen. This may be realized by sending many particles/photons through the 2-slit apparatus, one at a time. Given that exp(ip dot r) is an interaction probability (we argue), its relevance holds in the interaction region which is presumably of about a wavelength long or so. We argue that exp(i p dot r) exp(-i p dot r) = 1 does not mean that one should interpret the particle/photon as being possibly present at any r in space. The particle still has a center-of-mass which follows x=vt for a free particle. The only issue is that exp(ipx) implies that the particle does not interact at its center-of-mass point necessarily, but can interact with probability exp(ipx) at different points within .5 hbar/p of the center of mass on either side. As a result, we argue that there is no issue concerning localization of either a free particle or photon. The object is localized and moving at x=vt and it has a precise p which may render impulse hits at points about the center-of-mass point in keeping with exp(ipx). As a result, Heisenberg’s uncertainty relation (standard deviation p) (standard deviation x) >= hbar/2 does not hold for exp(ipx) because standard deviation p =0. exp(ipx) applies to a free particle which is not interacting. When the particle interacts (which is the way it is measured), then exp(ipx) becomes Sum over p a(p)exp(i p dot r). In such a case, a standard deviation of p and x arise. The Heisenberg uncertainty principle holds for interactions which are the only way the particle can be measured and so applies to W(x) and not a single exp(ipx). Given the above ideas, we suggest there is no reason to create a free particle wavepacket. Such a wavepacket seems to be created in the literature (1) in order to localize a particle in space and to ensure that Heisenberg’s uncertainty relationship is enforced. We have argued that there is no reason for this relationship if the particle is not interacting. As for localization, the free particle is localized by its center-of-mass in x=vt. It is just that one is not measuring this point. Furthermore, the increase in a Gaussian wavepacket’s x standard deviation in time is unphysical. Given that there is no reason for a wavepacket, we then question the notion of the wavepacket as being associated with a Bohmian potential which creates the wavepacket so to speak, i.e. -1/2m (d/dx dd/x A(x)) / A(x), where W(x,t) = A(x) exp(i S(x,t) ).