Belief in the Many-Worlds Interpretation Among Physicists

Introduction

The Many-Worlds Interpretation (MWI) of quantum mechanics has garnered significant attention in the physics community, particularly among scholars and practitioners of quantum mechanics. Sean Carroll, a prominent physicist and advocate of MWI, has explored this subject in his book 'Something Deeply Hidden'. This article delves into the beliefs and opinions of various physicists regarding MWI, examining how it fits into the broader landscape of quantum mechanics interpretations.

Beliefs and Consensus Among Quantum Physicists

Broadly speaking, physicists who delve into quantum mechanics, such as quantum condensed matter theorists, quantum information theorists, and high-energy theorists, generally share a consensus on certain interpretations. The Copenhagen interpretation, often cited as a lack of an interpretation, is not considered a valid theoretical framework. This is due to its incompatibility with ontology and its status as a physical theory.

Bohm’s pilot wave interpretation is also dismissed, primarily because it introduces relativistic causality violations and relies on post-measurement conditions that are unnecessary in standard quantum mechanics. This interpretation adds two assumptions that are not required anywhere else in physics. MWI stands out as a more straightforward approach, making no additional assumptions and aligning directly with experimental evidence.

Prevalence and Perception

The popularity of MWI is not as much about a consensus but rather a significant minority support. It's reported that a minority of physicists, primarily those studying quantum mechanics, favor MWI over other interpretations. This includes quantum information theorists and certain high-energy physicists. However, it is not safe to say there is a general agreement that it is the correct interpretation.

It is also worth noting that many physicists adopt an operational or epistemic approach, treating theories as provisional without necessarily striving for their ultimate truth. Some even believe that no final theory may exist, treating theories as mere approximations. Within this context, the MWI is viewed as a possible fundamental theory, given its nature as a cornerstone of quantum mechanics.

Subfield-Specific Preferences

Sean Carroll's comments on his podcast indicate that the preference for different interpretations varies across subfields. For instance, philosophers tend to favor hidden variable theories like Bohmian mechanics, while many cosmologists prefer MWI. Certain other fields have a large contingent of proponents of the objective collapse interpretation. This alignment with subfield groups is intriguing, as it suggests that the choice of interpretation might not be purely based on new, relevant information, but rather on the unsettled nature of the issues involved.

Some scholars choose to sidestep the issue altogether, either by pursuing an operational or epistemic approach, or by simply using the wavefunction for calculations without seeking further philosophical implications. This approach is common among both mathematicians and some physicists, who prefer to focus on practical applications over theoretical debates.

Conclusion

In conclusion, while the Many-Worlds Interpretation is not universally accepted, it has gained support among a significant minority of physicists, especially those in certain subfields. The varying preferences across different areas of quantum physics suggest that the truth of a theory might be more a matter of philosophical preference and subfield-specific norms than agreed-upon consensus. Further research, potentially through a more inclusive and representative poll, could provide a clearer picture of the true beliefs and preferences within the physics community regarding quantum mechanics interpretations.