3. Multiplicative Entropy -Energy Product Entropy: A New Analytical Framework for Understanding Irreversible Entropy Increase
If we adopt the concept of multiplicative entropy, it becomes much easier to understand why entropy increases spontaneously and irreversibly under the constraints of the second law of thermodynamics.
3.1. Definition of Multiplicative Entropy-Energy Product Entropy
I define multiplicative entropy as the product of the energies carried by each unit in a closed system. This definition of entropy is computable, and can also serve as an entropy coordinate for simulating the evolution of physical systems. When logarithmized, this multiplicative form reduces to the traditional additive entropy expression used in statistical mechanics.
Under the constraint of the second law of thermodynamics, energy always flows from units with higher energy to those with lower energy in a closed system. The total energy of all units remains constant (energy conservation), but the product of their energies keeps increasing — that is, the more uniform the energy distribution becomes, the larger the value of the multiplicative entropy.
When all units carry exactly the same amount of energy, the system reaches its maximum possible entropy — a state known as heat death.
This definition provides a much clearer and more intuitive description of entropy increase than the classical statistical formulation.
3.2. Quantum Thermodynamics Perspective
Speaking of quantum thermodynamics, if we assume that the quantum is the fundamental building block of space, then under the framework of a quantized space network, all states become analytic rather than statistical, specifically at the Planck time scale.
Let’s revisit the rule defined by the second law of thermodynamics: energy only flows from high-energy regions to low-energy ones. In essence, the process described by the second law — entropy increase — is a process of energy homogenization.
3.3. Comparison Between Multiplicative Entropy and Classical Statistical Entropy
| Dimension |
Multiplicative Entropy |
Traditional Statistical Entropy |
| Process Explicitness |
Yes, every step has clear changes |
No, only describes macroscopic end states |
| Preserves Microscopic Details |
Yes, path-dependent |
No, only cares about probability distributions |
| Has Temporal Directionality |
Yes, defined by local energy flow |
No, needs extra assumption for time arrow |
| Suitable for Simulations |
Yes, good for numerical modeling |
No, mainly used for theoretical analysis |
| Is an Analytical Function Form |
Yes, not based on statistical average |
No, relies on ensemble average |
Why Is Multiplicative Entropy More Suitable for Describing Energy Homogenization?
Take for example a system composed of N basic quanta. According to the second law, energy transfers from high-energy quanta to low-energy ones, gradually making the overall energy distribution more uniform.
Assume each quantum carries energy mᵢ. At any given transformation state, the total energy of the system is:
∑ mᵢ = constant; This satisfies energy conservation in a closed system.
How do we characterize the entropy change during this evolution? My proposed multiplicative entropy offers a more intuitive and precise analytical tool:
The entropy S of the system at a certain transformation state is defined as:
S = ∏ mᵢ
Under the constraint of energy conservation and directional energy transfer (from high to low), the more uniform the energy distribution becomes, the larger the product becomes.
When all quanta carry equal energy, the system reaches its maximum entropy — heat death occurs.
After applying the logarithm, this formula transforms into the classical additive entropy form. However, I argue that the multiplicative form more accurately captures the spontaneous and irreversible nature of entropy increase, offering greater clarity and visual intuition.
3.4. Computable Definition of Multiplicative Entropy: Time–Entropy Mapping
In this entropy definition, the entropy value of a closed system at a given moment (i.e., during a specific state transition) is calculated as the product of the energy norms of all space elementary quanta (SEQ) involved in the spatial transformation at that moment.
Analysis Formula of Entropy
In this definition of entropy, the entropy value of a closed system at a given moment (i.e., during a specific state transition) is calculated as the multiplicative product of the energy norms of all SEQ involved in that transition(that moment’s space transformation).
Sₘₐₓ≤mᵢⁿ , When all mᵢ are equal or differ only by Planck's constant h
(Where mᵢ refers to the energy carried by the ith SEQ during a single transformation of the closed system, where each energy state mᵢ is an integer multiple of Planck’s constant h, mᵢ=nᵢh, nᵢ∈N)
3.5. Energy Transfer Rules and Triggering Conditions:
Energy exchange occurs between adjacent SEQ (i,j) if and only if the following thermodynamic gradient exists: mᵢ>mⱼ+h, Energy transfer occurs only in discrete quanta of Planck's constant h, mᵢ→ mᵢ−h; mⱼ→mⱼ+h (Planck's constant:h)
Numerical Example: System States and Entropy Evolution
Table 1.
Simplified Entropy Increase Demonstration.
Table 1.
Simplified Entropy Increase Demonstration.
| System State |
SEQ Energy Distribution Etotal=∑mᵢ=12 |
Entropy S=∏mᵢ |
Remarks |
| Initial non-equilibrium state |
[3, 1, 5, 3] |
45 |
- |
| Intermediate state |
PathA [3, 1, 4, 4]; PathB [3, 2, 4, 3]; |
A48; B72; |
- |
| Final state |
PathA [3, 2, 3, 4]; PathB [3, 3, 3, 3]; |
A72; B81; |
Due to adjacent energy transfer with minimal quanta h, this system cannot reach maximum entropy in case A |
3.6. Logarithmic Relation:
After logarithmic transformation, lnS aligns with the conventional Boltzmann entropy form, while the multiplicative formulation naturally suits discrete systems.
3.7. Proof of Spontaneous Entropy Increase
Spontaneity Theorem of entropy increase (Second Law of Thermodynamics):
For every possible energy transfer process, the total entropy change satisfies ΔS≥0.
Proof Outline: Let the pre-transfer states be mᵢ=a, mⱼ=b (a>b+h);
The post-transfer entropy ratio is:
This demonstrates how entropy increases along various paths, reflecting the irreversibility and path dependence of thermodynamic processes in real systems.
Moreover, each system state can be assigned a unique entropy value — an "entropy coordinate" , which provides a powerful tool for computer simulations at the quantum level.
3.8. Analysis of the Maximum Entropy Principle
In the SEQ model, the maximum entropy principle is manifested through the driving tendency of entropy increase: energy not only flows from a higher-energy SEQ to an adjacent lower-energy SEQ, but it also follows the path with the largest energy difference.
For example, consider an SEQ i, which is adjacent to two other SEQ j and k. The energies carried by nodes i, j, and k are A, B, and C respectively, where A > B > C. In this case, there are two possible energy transfer paths from SEQ i according to the principle of entropy increase: path i→j or path i→k. We will analyze the entropy change for each path separately.
Under the constraint of energy conservation (i.e., A + B + C = constant), the entropy of the local system composed of these three SEQ before energy transfer is:S = A×B×C
Path i→j: transferring energy to node j (which has relatively higher energy):
Path i → k: transferring energy to node k (which has lower energy):
Here, "1" represents one unit of Planck constant h. Since B > C ⇒ BC + B > BC + C ⇒ S″> S′, the entropy increases more along the i→k path—that is, the path with the larger energy difference leads to a greater increase in entropy.
This deduction can be easily generalized to cases where the number of adjacent nodes is greater than two, so a detailed proof is omitted here.
However, it should be emphasized that the path with the maximum energy difference is not necessarily unique. Therefore, for states that have not yet occurred, the future still retains sufficient degrees of freedom — the evolution is not entirely deterministic.
From the perspective of this model, the apparent randomness in the wave function described by the Schrödinger equation arises from the non-uniqueness of the maximum entropy path—multiple microscopic energy redistribution trajectories, giving rise to probabilistic outcomes without requiring fundamental indeterminism.
3.9. Dimensional Structure in the Model: Dimensionless Energy and Entropy
In this model, all physical quantities are reconstructed based on the quantization of Planck’s constant ℎ. Energy is defined as discrete units carried by Space Elementary Quanta (SEQs), with each SEQ carrying an energy value that is an integer multiple of ℎ, i.e., mᵢ = nᵢℎ, where nᵢ ∈ ℕ. Since ℎ is normalized as a natural unit, energy becomes a dimensionless counting variable—representing the distribution of "energy quanta" across the system.
Accordingly, entropy is defined as the product of all SEQ energy values: S = ∏ mᵢ. Since each mᵢ is already dimensionless (normalized relative to ℎ), their cumulative product remains dimensionless. This definition frees entropy from reliance on statistical ensembles or probability weights, making it a directly computable, path-dependent dynamical variable capable of precisely characterizing evolution through every energy redistribution event.
Given the model’s prior assumption that each Space Elementary Quantum (SEQ) possesses a ground-state energy quantized in integer multiples of ℎ ,[
3] the energy value of every mᵢ is at least 1; consequently, in this framework, the multiplicative entropy of any physical system is strictly greater than 1.