Corrections to  Second Edition, 2nd revision (July 2015)   of

Student Friendly Quantum Field Theory

 

Note: 1st edition and 2nd edition (prior versions) users also need to check this 2nd edition, 2nd revision corrections page for additional corrections.

 

Sorted by Page Number:  This Page

Sorted by Date Posted:  Click Here

 

 

 

Significant Corrections (may impact learning process)

 

 

Pg

Chap

Date Posted

Significant Correction

Reported by

(blank = the author)

10

1

Oct 13, 2017

Prob 6, 3rd line: before “determine”, insert - assuming p_x is a single term, -

Harm van der Lek

11

2

Aug 6, 2015

Sect. 2.1.1, point 2. After “mass”, insert - at rest -

Michael Heiss

21,31

2

May 31, 2017

I was a bit sloppy in two blocks near the ends of Wholeness Charts 2-2 and 2-5. See corrections at Changes to Charts 2-2 and 2-5. As I noted in the text, it may be best not to get too deeply into Chart 2-2, as it is primarily a summary of classical variational mechanics, and the changes made here relate to subtle aspects of that theory, which are not so relevant for QFT.

Allan Tameshtit

23

2

Aug 6, 2015

Box 2-2. My purpose in this box was to give a derivation of (B2-2.3) that was much simpler than that in other books. There are some subtleties involved, but it is best not to worry about them until after you have mastered QFT. If at that time, you feel up to it, check out Box2_2_comments

 

27

2

Apr 6, 2016

Eq (2-37). Some further explanation plus some changes related to (2-37) are in order. See  Comments on (2-37).

Tom Bartholet

30

2

Aug 6, 2015

For versions prior to July 2015, this was OK. For the July 2015 version, equations (2-42) and (2-43). The “i” subscript on delta would be better as a superscript. Ultimately, it doesn’t really matter, but it helps the parallel with (2-44) if “i” is superscripted.

 

54

3

Aug 17, 2015

The k’s in the numerators (two places) in the second line of (3-52) should have superscripts, not subscripts. (3-52) as written, strictly speaking, is still correct, as there are two k's with subscript i multiplied, which equal two k's with superscript i multiplied. But this correction should eliminate confusion.

Steffen Leger

61

3

May 8, 2017

Mid page, after 2nd paragraph after “Caveat”.

If normal ordering were only used in QFT to get a Delta E energy level (as that is all that is relevant in classical theory) one might concede some justification for it. However, as one will see in Chap 4 (pg. 112 after “End of Derivation”), it is also commonly invoked to get the correct charge operator for spin 1/2 fields. Otherwise, the vacuum would have an infinite charge. Since we have no theories where that can simply be subtracted, it is hard to justify use of normal ordering for charge derivation, and one’s confidence in it is further eroded.

Note that on pg. 112, I present an alternative derivation to the charge operator that does not depend on normal ordering.

 

73

3

June 16, 2016

1st line after (3-122). The first “factor” in (3-122) is GF of (3-120). The second “factor” in (3-122) is HF of (3-120). In teaching a QFT course, I was asked by a student “where did the GF and HF of (3-120) go?”

Lou Biegeleisen

74

3

Mar 2, 2016

Last line on page: After the comma, insert  we have the Cauchy integral formula -

Tom Bartholet

76

3

Sept 29, 2016

The line after (3-140). It is correct as is, but maybe easier to understand if we change “the route” to  which route (loop) -

 

79

3

Apr 1, 2016

In (3-150), change partial time derivative to total derivative. In next line, after “field,” insert  with the aid of Box 2.1, pg. 22,  

Tom Bartholet

111

4

May 16, 2016

Sect. 4.6.3, last sentence. Change “d_r dagger” to  d_r - . Change “annihilates that state” to - results in the vacuum |0 > -

Tom Bartholet

127

4

May 16, 2016

2nd paragraph of Conclusion #1:  Insert at beginning of paragraph:  For Fig. 4-5(b), . After “Changing v”, insert  (without aligning it with S)  After “Therefore,”, insert  in Fig. 4-5(b) -

Tom Bartholet

142

5

June 16, 2016

(5-35) top row. This is correct as it is, since dummy indices can be used interchangeably. However, it can be easier to understand if the mu and nu superscripts on the epsilons on the RHS of each equal signed are switched.

Tom Bartholet

142

5

June 16, 2016

(5-36). The r’s after the second equal sign should be underlined, as there is no sum.

Tom Bartholet

147

5

June 16, 2016

(5-50). The summations should only be over r, not k. The integral is over the range of k.

Tom Bartholet

158

5

May 16, 2016

Wholeness Chart 5-4, 4th row, 2nd column on page. Put a bar over rho. Two places. (rho is an expectation value not an operator here.)

Tom Bartholet

159

5

May 16, 2016

Wholeness Chart 5-4, 2nd row up from bottom on page: After “two commutators” insert - /anti-commutators -

Tom Bartholet

160

5

May 16, 2016

Wholeness Chart 5-4, top row on page: After “two commutators” insert - /anti-commutators -

Tom Bartholet

169

6

July 7, 2016

Eq. (6-14). The arguments for the vector and tensor on the RHS of their respective equal signs should not have a Lambda^alpha_beta before the x^beta. Two places. (And it might look neater to change the beta on the x to an alpha, but not essential.)

Tom Bartholet

176

6

Aug 22, 2016

Eq (6-41). The first minus sign (before N_b) should be a plus sign.

Tom Bartholet

184

7

June 22, 2016

Eq. (7-8). The minus sign in front of “e” should be a plus.

 

186

7

Oct 27, 2016

(7-19): Comparing with (7-16), one might wonder about the change in order of the QFT field operators (photon and fermion) after the equal sign. The order here is not important, as fields associated with different types of particles commute. Amu commutes with psi here.

Tom Bartholet

198

7

Sept 22, 2016

Sentence just above Sect 7.5.2, change “(7-62)” to - (7-63) -.

Tom Bartholet

205

7

May 9, 2017

First paragraph following (7-82), “C3D4= - D3C4” should be “C3D4= - D4C3

Tom Bartholet

211

7

Nov 11, 2016

(7-109): The first three terms on the second line should have the Nc operator in front of them.

(7-110). The last term in the top row should have the Nc operator in front.

Tom Bartholet

217

8

May 9, 2017

(8-9), after 2nd equal sign: The Sfi should be inside the Sigma and all f except that in the bra should be primed.

Tom Bartholet

231

8

May 9, 2017

(8-74) and (8-75) both need to insert “i” in front of the expression for SF

Tom Bartholet

231

8

Jan 16, 2017

3rd line after (8-79): Change “denotes antiparticles.” to   is sometimes used in Feynman diagrams for virtual antiparticles. It is just a symbol. The overbar here is not related to adjoint fields.  

Vasudev Godbole

235

8

May 9, 2017

(8-89): Insert a delta function with argument zero on the RHS outside the integral.

Tom Bartholet

239

8

May 12, 2017

First line: insert “ e” after equal sign.

Tom Bartholet

247

8

June 16, 2016

2nd paragraph up from bottom of page. At end of sentence, add   or to interactions that can be renormalized away (not treated in this text).  

 

271

10

May 8, 2017

Sect. 10.2.4. Actually, the Fulling-Davies-Unruh effect is not related to the  quanta, the higher order corrections, nor the 3 virtual particle bubbles, but to a more advanced concept in QFT related to time dependent Hamiltonians. Finding it in an experiment would not really be a proof of zero point energy in the usual  quanta sense.

 

274

10

June 16, 2016

(10-8), top row. Don’t hold up your study of QFT by spending much time on this fairly advanced material. Someday I may re-write this section with these changes. Each 1/2, should be multiplied by a delta(0), i.e., a Dirac delta function with argument zero. This also applies to every relation on the next 2-3 pages with a 1/2 term. See links on book website for Continuous Solutions for reasons why. From that one could also see why comments in this part of the text for single 1/2 quanta particle wave packet in “all space” should refer to “unit volume”.

 

281-283

10

June 16, 2016

WhCh 10-2. Wherever there is a continuous solutions form with 1/2 inside the integral, it should be a multiplied by a factor delta(0), i.e., a Dirac delta function with argument zero. See links on book website for Continuous Solutions for reasons why.

 

298-299

11

June 13, 2017

(11-42) insert minus sign after 2nd equal sign. (11-44). same change (minus sign) after each equal sign.

Tom Bartholet

310-311

12

Aug 21, 2017

(12-16): delete the minus sign after the equal sign (2 places).

((12-18), 4th line: change minus sign on LHS to plus sign

(12-21), last line: change minus sign on LHS to plus sign

Tom Bartholet

310

12

Sept 11, 2017

Comment (not correction) on (12-17) RHS: The superscript (2) might be confusing. Here the notation, along with the subscripts, means we take the 2nd order in e form of the amplitudes but use the modified versions for e, photon propagator, and vertex gamma matrix (as described in under bracket note).

Tom Bartholet

323

13

Oct 13, 2017

Fig. 13-1: Under the first diagram, insert ieo2 before Pi. Under the 2nd diagram, insert ieo2 before Sigma. In the 3rd diagram, insert ieo3 before Lambda.

Add to text above the figure: Applying Feynman’s rules in Fig. 13-1, excluding the incoming and outgoing particles, yields the amplitudes under each diagram, where the symbols are defined in (13-1) to (13-3).

Tom Bartholet

328

13

Oct 13, 2017

7th line down on page: Change “each of these terms must equal zero” to - these terms must sum to zero -

Tom Bartholet

337a

13

Oct 13, 2017

(13-83): both lines need a summation over r symbol inserted

(13-84): needs same summation over r inserted

Tom Bartholet

337a

13

Oct 13, 2017

Paragraph after (13-84): the operator atilde_r(k) should have a summation over r symbol in front of it. Same for adagger-tilde_r(k).

Tom Bartholet

340

14

Aug14, 2017

(14-1), 1st line: Delete “p’ = “

Vasudev Godbole

384

15

May 8, 2017

I have recently realized that cut-off regularization has a more obvious reason for why it doesn’t work. It is not Lorentz invariant, as the upper limit on our integral (max energy) is not Lorentz invariant (energy for the same object changes as seen in different frames). The other three regularization methods discussed are all Lorentz invariant, and they all produce the correct result.

 

462

17

Oct 25, 2017

(17-94): Notation under the Sigmas should be r′1 = 1,  r′2 = 1 … r1 = 1, r2 = 1, respectively.

John Davidson

480

17

May 8, 2017

(17-175): the numerators should all have a “ + m” in them.

Zhang Juenjie

 

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Minor Corrections (should not impact learning process)

 

Pg

Chap

Date Posted

Minor Correction

Reported by

x

 

Sept 30, 2016

Acknowledgements for 2n Ed, end of first paragraph. Move comma after “them” to after “thank”

 

xi

Pre-face

Oct 19, 2015

7th line: after “orthodox” insert  (pedagogically) -

 

2

1

Sept 30, 2016

2nd line above (1-1), delete comma at end of the line

 

20

2

Sept 1, 2015

Wholeness Chart 2-2, left column, 4th row up from bottom: Change “Hamiltonian’s Equations of Motion” to -Hamilton’s Equations of Motion” -

Tom Bartholet

23

2

June 16, 2016

Box 2-2. Eq (B2-2.3) number not aligned.

 

43

3

Oct 11, 2016

Eq (3-9). May be good to insert “This is a solution given En2 - pn2 = m2”.

Jeroen Spandaw

45

3

Oct 25, 2017

Just above (B3-1.7): after “probability current”, insert  (density) -

Qingzhong Wu

50

3

Mar 23, 2016

Eq. (3-37). Delete extra RH parenthesis on eq number.

Juan José Bigeón

51

3

Sept 10, 2015

Sect. 3.2.4, 1st line: change “of this and” to  of this chapter and  

Tom Bartholet

61

3

Oct 25, 2017 addition to

May 8, 2017 note

Normal ordering is also commonly used for another (more complicated) matter, as discussed in pgs. 208-209. I discuss an alternative way to handle that issue in those pages.

 

65

3

Aug 6, 2015

Mid page, Note on Nomenclature line: “solution” should have an - s -  on the end.

 

79

3

Aug 6, 2015

Mid page, Odds and Ends section: After “3-1” insert - (pg. 65) -. After “3-2”, insert - (pg. 68) -.

 

87

4

Jan 25, 2016

3rd line from bottom of page: change “one the” to  one of the -

Pavel Fadeev

88

4

June 21, 2016

2nd paragraph up from bottom, first sentence. Exponent +/- kx should be =+/- ikx.

Lou Biegeleisen

96

4

Aug 6, 2015

4th margin note: subscript 1 on u should not be italic

 

107

4

Aug 6, 2015

Box 4-3. Equation numbers not aligned.

 

127

4

Sept 30, 2016

mid page. bold 1/2 before ket should be not bold

 

131

4

Sept 30, 2016

In title of Sect 4.14.5, “The” should not be capitalized

 

143

5

June 16, 2016

Footnote paragraph is indented and shouldn’t be.

 

144

5

Sept 23, 2016

(5-42). It will be better here if we take A^mu to be A_mu. It doesn’t matter which we use, but later in Chap 7 we do it with a subscript mu, not a superscript. So we change it here to be consistent

Tom Bartholet

147

5

Jan 25, 2016

Sect. 5.3.1, change “pg. 155” to ‘ pg. 156 -

Pavel Fadeev

160

5

Aug 6, 2015

4th row down in the wholeness chart, last line: Delete open parenthesis at beginning of the line.

 

166

6

Aug 6, 2015

6th line down: Change “functional” to - the function -.

 

170

6

Oct 7, 2015

First margin note on page: eliminate underline on e’.

Michael Koren

177

6

June 22, 2016

Top line on page: After “this means” insert - using the LHS of (6-39) - .

 

177

6

Aug 22, 2016

In the third line of Sext 6.6.1, it is better to have the page range for 135-141 rather than 138-141.

Tom Bartholet

184

7

Sept 22, 2016

Margin note for eq (7-6) should be - gauge - instead of “gage”

Tom Bartholet

188

7

Aug 6, 2015

Wholeness Chart 7-1. 4th row up from bottom, Operators column. Superscript S is wrong font.

 

199

7

Nov 7, 2016

Sect. 7.5.3, 2nd paragraph, beginning: After “Fig. 7-1” insert - and Wholeness Chart 7-2 -

Tom Bartholet

211

7

Aug 6, 2015

1st line above (7-110): insert a comma after “them”.

 

211

7

Aug 6, 2015

(7-110), 2nd line: Boxes with 8, 9, and 10 in them should be above the terms, rather than below them.

 

221

8

May 9, 2017

(8-24): “Bhabba” should be “Bhabha”

Tom Bartholet

224

8

May 9, 2017

(8-42), “r” subscript of “ν” should be primed

Tom Bartholet

225

8

May 9, 2017

Fig. 8-3 would probably be better with the first vertex on each side labeled x2 and the second x1, as it would track the text better. But it is common to not write in the coordinate labels at each vertex in Feynman diagrams, so the reader needs to get accustomed to the practice.

Tom Bartholet

231

8

May 9, 2017

(8-76) and (8-78): Dmu nu should be DF mu nu

Tom Bartholet

235

8

May 9, 2017

End of 1st paragraph in Sect 8.5, change “delta function” to “Dirac delta function”.

Tom Bartholet

236

8

May 9, 2017

3rd Feynman rule: iSF should be iSF (p)

Tom Bartholet

241

8

May 9, 2017

First margin note should refer to Chap. 16, not Chap. 17.

Tom Bartholet

219

8

Dec 8, 2016

This is not a correction, but an added problem.

Box 8-1. At the end of the box, add “Do Prob. 18 for more insight on this.” Then, add, at the end of the chapter.

Prob. 18. Draw the mass shell for a photon. Suppress the k2 and k3 dimensions, to make it easier. That is, plot E vs k1. Does it touch the origin? Are the sides of the shell, for a photon, straight lines? Does the mass shell for a massive particle like that shown in Box 8-1 approach that of a photon asymptotically for very high E (speed approaching c)?

Tom Bartholet

256

9

May 12, 2017

Fig. 9-1, RHS: Reverse the arrow on the lower line to make it a positron.

Tom Bartholet

258

9

May 12, 2017

Box 9-1, 3rd paragraph up from bottom, 2nd line: After “x1x3x2”, insert - in (B9-1.3) -

Tom Bartholet

259

9

May 12, 2017

(9-7): It may be easier to follow if the SF(p) gamma^mu were moved to after the gamma^nu. Given that these factors are inside the trace, it doesn’t really matter, but the whole thing tracks Fig. 9-5 better if it is done this way.

Tom Bartholet

261

9

May 12, 2017

(9-13): Put a factor of 1/(2 pi)2 after the equal sign.

Tom Bartholet

262

9

May 12, 2017

Line above (9-16): After “natural” insert - and Heaviside-Lorentz -

Tom Bartholet

264

9

Sept 30, 2016

Next to last bullet near bottom of page: delete space after “Compton”

 

285b

10

May 24, 2017

Prob. 1, 2nd line: The quantity inside the bra should not be the complex conjugate of the quantity inside the ket, but the same thing. The bra notation implies the quantity shown inside, when expressed mathematically, has the complex conjugate taken.

Tom Bartholet

282

10

May 24, 2017

Last row, 2nd column: The quantity inside the bra should not be the complex conjugate of the quantity inside the ket, but the same thing. The bra notation implies the quantity shown inside, when expressed mathematically, has the complex conjugate taken.

Tom Bartholet

285

10

May 24, 2017

Section 10.12, Appendix E: It is clearer if whenever the term “delta function“ is used, it is replaced with “Dirac delta function” (so as not to confuse with the Kronecker delta).

Tom Bartholet

324

13

Oct 13, 2017

2nd paragraph after (13-9): Argument k for Pi_c should be k2

Tom Bartholet

328

13

Oct 13, 2017

1st line after “End of Proof”; change “photon loop” to - fermion loop -

Tom Bartholet

329

13

Oct 13, 2017

(13-36): each denominator should have a “+ epsilon” added

Tom Bartholet

330

13

Oct 13, 2017

Paragraph after (13-40): After “typically)”, insert  - , in the sense that it gives rise to a corresponding vertex in a Feynman diagram -

Tom Bartholet

331

13

Oct 13, 2017

2nd line after (13-42): before “photon” insert  external -

Tom Bartholet

332

13

Oct 13, 2017

(13-49): Right near end of equation, for Sigma_c, the p argument should have a slash through it.

Tom Bartholet

334

13

Oct 13, 2017

1st line after (13-56) In the expression right after “Also,”, delete the - i -.

Tom Bartholet

337

13

Oct 13, 2017

(13-78), 4th line down: operator adagger_r” needs an argument (k”).

Tom Bartholet

371

14

Aug 6, 2015

Page heading should be “Section 14.9 Chapter Summary”. Heading as shown should have “mu” instead of a box (2 places). Computer glitch in 2nd ed. Not in 1st.

 

403

16

Oct 25, 2017

5th line up from bottom: Change “.)” to - ). -

John Davidson

414

16

Oct 25, 2017

2nd line above (16-48): underlining on mu mu subscripts should be raised.

John Davidson

414

16

Oct 13, 2017

(16-48) next row up from bottom: Superscript “30” should be - 20 -

John Lynch

457

17

Oct 25, 2017

(17-60): bold p’ in underbracket should have “1” subscript inside the absolute value sign

John Davidson

463

17

Aug 6, 2015

(17-99). “1/4” font size too big.

 

491

18

June 22, 2016

Paragraph to the right of Fig. 18-1, 3rd line: The underline marks in the argument of the delta function should just be spaces.

 

508

18

Aug 6, 2015

Wholeness Chart 18-6. Title needs to be centered

 

515

19

Aug14, 2017

3rd line up from bottom re Cutoff Regularization: after “gauge invariance” insert  and is not Lorentz invariant . Delete “a” and insert  s - after “underpinning.

 

520

19

June 21, 2016

Footnote 1. The year should be 2010, not 2002.

 

524

Index

Oct 25, 2017

“Lorentz gauge” should be  Lorenz gauge -

John Davidson

524

Index

May 12, 2017

After “Normal ordering, 60”, insert - 112-113, 208-209 -

 

 

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